Add remote development PoC docs

What does this MR do and why?

Add documentation related to the PoC for Remote Development.

Related - &8868 (closed)

TODOs

While the docs are being been reviewed, the following things are pending

• Make https://gitlab.com/gitlab-com/create-stage/editor-poc/remote-development/gitlab-rd-web-ide-docker public so that folks can pull docker images from it.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.