This PR is a continuation of
https://github.com/paritytech/polkadot-sdk/pull/2102 and part of an
initiative started here https://hackmd.io/@romanp/rJ318ZCEp
What has been done:
- The content under `docs/*` (with the exception of `docs/mermaid`) has
been moved to `docs/contributor/`
- Developer Hub has been renamed to Polkadot SDK Docs, and the crate has
been renamed from `developer-hub` to `polkadot-sdk-docs`
- The content under `developer-hub/*` has been moved to `docs/sdk`

---
Original PR https://github.com/paritytech/polkadot-sdk/pull/2565, it has
been close due to too many rebase conflicts

---------

Co-authored-by: Serban Iorga <serban@parity.io>
Co-authored-by: Chevdor <chevdor@users.noreply.github.com>
Co-authored-by: Egor_P <egor@parity.io>
Co-authored-by: Bastian Köcher <git@kchr.de>

Using taplo, fixes all our broken and inconsistent toml formatting and
adds CI to keep them tidy.

If people want we can customise the format rules as described here
https://taplo.tamasfe.dev/configuration/formatter-options.html

@ggwpez

, I suggest zepter is used only for checking features are
propagated, and leave formatting for taplo to avoid duplicate work and
conflicts.

TODO
- [x] Use `exclude = [...]` syntax in taplo file to ignore zombienet
tests instead of deleting the dir

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Bastian Köcher <git@kchr.de>

Adds a config file that allows to run `zepter` without any arguments in
the workspace to address all issues.
A secondary workflow for the CI is provided as `zepter run check`. Both
the formatting and linting are now in one check for efficiancy.

The latest version also detects some more things that `featalign` was
already showing.

Error message [in the
CI](https://gitlab.parity.io/parity/mirrors/polkadot-sdk/-/jobs/3916205)
now looks like this:
```pre
...
crate 'test-parachains' (/Users/vados/Documents/work/polkadot-sdk/polkadot/parachain/test-parachains/Cargo.toml)
  feature 'std'
    must propagate to:
      parity-scale-codec
Found 55 issues (run with --fix to fix).
Error: Command 'lint propagate-feature' failed with exit code 1

Polkadot-SDK uses the Zepter CLI to detect abnormalities in the feature configuration.
It looks like one more more checks failed; please check the console output. You can try to automatically address them by running `zepter`.
Otherwise please ask directly in the Merge Request, GitHub Discussions or on Matrix Chat, thank you.

For more information, see:
  - https://github.com/paritytech/polkadot-sdk/issues/1831
  - https://github.com/ggwpez/zepter
```

TODO:
- [x] Check that CI fails correctly

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add markdown linting

- add linter default rules
- adapt rules to current code
- fix the code for linting to pass
- add CI check

fix #1243

* Fix markdown for Substrate
* Fix tooling install
* Fix workflow
* Add documentation
* Remove trailing spaces
* Update .github/.markdownlint.yaml

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
* Fix mangled markdown/lists
* Fix captalization issues on known words

* update contribution guidelines, remove redundant files

* removing doc ref labels, updating links on contribution

* add manifest formatting

* update title

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* update links to the new repo

* terminal friendly convention

* update doc guideline format

---------

Co-authored-by: Alexander Samusev <41779041+alvicsam@users.noreply.github.com>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* CI: Add feature sorting check

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Sort all features

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add some mistakes

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Revert "Add some mistakes"

This reverts commit b2b1099f979f6decb22d09b46689c1554bb72e81.

* CI job naming

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add oneliner formatting

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Explain tool

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Use latest version

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Better erorr message

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Format after master merge

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Use --check option

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Messed up the merge commit...

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* moved client code out of primitives

* bump ci

* Fixup from merge.

* Removed unused deps thanks to review feedback

* Removing unneeded deps

* updating lock file

* note about rustfmt

* fixed typo to bump ci

* Move lonely CacheKeyId to parent

* cargo fmt

* updating import style

* Update docs/STYLE_GUIDE.md

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Remove dead link to out-of-date style guide

* Replace dead link with self-hosted doc

* Use relative link to style guide

Co-authored-by: Benjamin Kampmann <ben@gnunicorn.org>

* Format style guide

Co-authored-by: Benjamin Kampmann <ben@gnunicorn.org>

* Formatting

Co-authored-by: Benjamin Kampmann <ben@gnunicorn.org>