Since 2023-09-21, Element X is no longer beta. See https://element.io/blog/element-x-ignition/

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

People should be made aware of the status of this component as soon as
possible.

This is consitent with the positioning of Note messages we have for other deprecated
components (e.g. bot-chatgpt, bot-go-neb, etc).

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3735

* Update configuring-playbook-sliding-sync-proxy.md

* Update README.md

* Apply suggestions from code review

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

---------

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Based on MSC3575

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

This adopts the structure of docs/configuring-playbook-matrix-authentication-service.md which was recently created.

- …
- Adjusting the playbook configuration
  - …
  - Adjusting the (service name here) URL
  - …
- Adjusting DNS records
- Installing
- …

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

* Remove mention of Android Element X being less feature complete than iOS version

Quoting upstream:

> Element X Android and Element X iOS apps are in a similar state.
> 
> https://github.com/vector-im/element-x-android/issues/911

* Update configuring-playbook-sliding-sync-proxy.md

* fixes #2586

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2515