(CI) TDB (IPROTO): Update CI for doc building and publishing (add version 3.0.0) to the version chooser

[xuniq]

Product: TDB 3.0.0
Since: 3.0.0
Root document:

• https://www.tarantool.io/ru/tdb/doc/latest/

SME: @ a1div0 @ lastoCHka42 @ Galiev-Ruslan
Doc deploy instruction: https://confluence.vk.team/pages/viewpage.action?pageId=1380111583#id-%D0%94%D0%B5%D0%BF%D0%BB%D0%BE%D0%B9%D0%B4%D0%BE%D0%BA%D1%83%D0%BC%D0%B5%D0%BD%D1%82%D0%B0%D1%86%D0%B8%D0%B8-%D0%94%D0%B5%D0%BF%D0%BB%D0%BE%D0%B9docx

Details

Currently, the TDB docs are deployed to test and prod environment from two branhes:

• release-1x/master branch (1.x version in the version chooser);
• release-2x/master branch (latest version in the version chooser).

With the 3.0.0 release, we need to update CI for TDB docs. The new pipelines should deploy test and prod documentation for 3 versions:

• 1.x - will be published from the release-1x/master branch
• 2.x - will be published from the release-2x/master branch
• [NEW] latest (3.x+) - will be published from the ? branch

What needs to be done

1. Discuss the version naming with PM and @ a1div0
2. Update naming for the latest version in the version chooser. The new naming: latest (3.x+) ?
3. Enable doc build and deploy (test and prod) for the new master branch. The docs from this branch are to be published as the latest (3.x) version in the version chooser.

Definition of done

• Enabled GitLab workflow for building and publishing TDB 3.0.0 docs on test and prod env from the corresponding branch.
• This workflow publishes the docs as the latest (3.x+) version in the version chooser on Tarantool website.
• Enabled GitLab workflow for building and publishing TDB 2.x docs on test and prod env from the release-2x/master branch.
• The docs from release-2x/master are published on prod as the 2.x version in the version chooser on Tarantool website.
• If there is no doc version in the URL or the stated version doesn't exist, the site redirects to the latest (3.x) docs.
• Add redirects if necessary