Uses custom metadata to exclude chain-specific crates.  
The only concern is that devs who want to use chain-specific crates,
still need to select matching versions numbers. Could possibly be
addresses with chain-specific umbrella crates, but currently it should
be possible to use [psvm](https://github.com/paritytech/psvm).

---------

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

Co-authored-by: Bastian Köcher <git@kchr.de>

A brief explanation of the Deprecation Checklist is added to the
Contributing notes with a link to it

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>

## Overview

This PR brings in the new version of prdoc v0.0.6 and allows:
- local schema
- local config
- local template

It also fixes the existing prdoc files to match the new schema.

## todo

- [x] add a brief doc/tldr to help contributors get started
- [x] test CI
- [x] finalize schema
- [x] publish the next `prdoc` cli version (v0.0.7 or above)

---------

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>

- Updated ./docs/CONTRIBUTION.md to clarify how to use command bot and
update ui-tests locally or in PR
- Moved update-ui-tests.sh to a root of project to run them along for
substrate and polkadot together

---------

Co-authored-by: Mira Ressel <mira@parity.io>

# Description

*Please include a summary of the changes and the related issue. Please
also include relevant motivation and context,
including:*

- What does this PR do?

This PR fixes two minor typos in the contributing top level docs, and
fixes a broken link to another file.

- Why are these changes needed?

While reading the guidelines I noticed two small typos and a broken link
to the documentation guidelines in the same directory.

- How were these changes implemented and what do they affect?

Both typos were fixed. The file has been renamed from
`DOCUMENTATION_GUIDELINE.md` to `DOCUMENTATION_GUIDELINES.md` to match
the link, as the link seems correct vs the filename. There are no other
references to this file within this repo.

There are no open issues related to this

* Add test prdoc
* Prepare for the check
* Escape PR number
* Fix conditional step
* Add checkout and actual check
* Cleanup
* Minor fixes
* Add doumentation
* Add more doc

* 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

* Added root README.md draft

* Modified Contribution section to reflect unified guidelines

* Update README.md

Co-authored-by: Squirrel <gilescope@gmail.com>

* Expand Substrate description

* Added Badges and Upstream deps

* Fixed badge links

* Fixed CONTRIBUTING.md links, added security and resources section to root README.md

* Moved runtimes link to Polkadot section

---------

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

* add link to labels doc

* add absolute links in PR template

* Update docs/CONTRIBUTING.md

* 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>