* Dapps web

Conflicts:
	dapps/src/apps/fetcher.rs
	dapps/src/handlers/fetch.rs

* Rewriting fetch

* Parity-wide fetch service

* Obey the limits and support cancellation.

* Removing temporary files.

* Actually use Fetch for dapps

* Re-implementing file fetching to avoid temporary files.

* Serde to 0.8.19

* Fixing content & dapps fetch

- Move Updater into its own crate.
- Change ethcore -> parity in authors, homepages and licenses.

* Getting rid of old dapps

* Updating proxypac and allowing home.parity on signer

* CORS support for API

* Fixing CORS - origin is sent with protocol

* Fixing signer with proxy

* Fixing grumbles

* Fix expect msg [ci:skip]

* Refactoring dapps to support API endpoints.

* Using ContentHandler for unauthorized requests

* Extracting url stuff

* Adding ping endpoint

* CORS support for ping request

* Fixing url.is_none()

* minor formatting fix

[ci:skip]

* Refactoring dapps to support API endpoints.

* Using ContentHandler for unauthorized requests

* apps list to separate module

* Preparing to support serving files from disk

* Serving files from disk

* Using dapps path from CLI

* Adding more docs

* Renaming dapps repos. Updating dapps

* Skipping legacy options for compatibility. Fixing tabs

* Fixing CLI options

* Proxy.pac serving

* Subdomains router for dapps

* Proper handling of prefixed and non-prefixed apps

* Changing dapps domain to parity