Cut 8.7/8.8 split alpha docs

[pepopowitz]

Due: Tuesday, February 11.

Cut the 8.7 version of the docs, but retain an unreleased state of them, so that we have both 8.7 and 8.8 unreleased versions.

See #4894 for inspiration on cutting two unreleased versions.

Acceptance criteria

• Main docs Version 8.6:
  • is sourced from /versioned_docs/version-8.6/
  • is served from /docs/path/to/doc/
  • has C8 REST API docs re-generated from the camunda/camunda 8.6.8 tag [done in chore: update 8.6 c8 rest api docs #4957]
• Main docs Version 8.7:
  • is sourced from /versioned_docs/version-8.7/
  • is served from /docs/8.7/path/to/doc/
  • has 8.7 C8 REST API docs re-generated from the camunda/camunda stable/8.7 branch [NOTE: this will come after the initial docs release]
  • shows "8.7 (Unreleased)" in the version dropdown
  • shows "8.7 (Unreleased)" in the navbar when selected
  • shows "8.7 (Unreleased)" in the badge on any individual doc
• Main docs Version 8.8:
  • is sourced from /docs/
  • is served from /docs/next/path/to/doc/
  • has C8 REST API docs re-generated from the camunda/camunda main branch
  • shows "8.8 (Unreleased)" in the version dropdown
  • shows "8.8 (Unreleased)" in the navbar when selected
  • shows "8.8 (Unreleased)" in the badge on any individual doc
• Optimize docs Version 3.14:
  • is sourced from /optimize_versioned_docs/version-3.14.0/
  • is served from /optimize/path/to/doc/
• Optimize docs Version 3.15:
  • is sourced from /optimize_versioned_docs/version-3.15.0/
  • is served from /optimize/3.15.0/path/to/doc/
  • shows "8.7 / 3.15.0 (Unreleased)" in the version dropdown
  • shows "8.7 / 3.15.0 (Unreleased)" in the navbar when selected
  • shows "8.7 / 3.15.0 (Unreleased)" in the badge on any individual doc
• Optimize docs Version 3.16:
  • is sourced from /optimize/
  • is served from /optimize/next/path/to/doc/
  • shows "8.8 / 3.16.0 (Unreleased)" in the version dropdown
  • shows "8.8 / 3.16.0 (Unreleased)" in the navbar when selected
  • shows "8.8 / 3.16.0 (Unreleased)" in the badge on any individual doc

[akeller]

This looks correct and is an important reminder we need to rip out the separate Optimize instance now that those are distinctly separate - Optimize for C7 and C8.

has 8.7 C8 REST API docs re-generated from the camunda/camunda stable/8.7 branch

This assumes the API team has done the cleanup work or whatever was necessary to make this branch reflect what is actually shipping with 8.7 (copy of 8.6 with features added or some other rework).

[pepopowitz]

This looks correct and is an important reminder we need to rip out the separate Optimize instance now that those are distinctly separate - Optimize for C7 and C8.

Yes, this was my biggest question mark with these! I'm adding a card to our 1:1 next week to talk about this work, to get a better sense of the specifics.