[WIP] Added documentation for experimental microservice versioning feature

[AmeliaEScott]

Related:

• Microservice versioning document
• https://github.com/PX4/Firmware/pull/13565
• https://github.com/mavlink/qgroundcontrol/pull/8065

This PR is part of the experimental microservice versioning feature.

NOTE: THIS CANNOT BE MERGED YET, as the associated firmware changes and service are not done.