update docsite embeddings automatically

[hanna-paasivirta]

Short Description

Add
a) github action to update apollo embeddings when docsite is updated
b) Add a step to enable using the latest collection by default

Fixes #173

Implementation Details

a) todo:

• set github action and script trigger
• adjust naming convention to have more precise time (YYYYMMDDhhmm) in case there are multiple docsite udpates in a day
• add step to then delete oldest collection if there's more than 3 collections with the name format "docsite-YYYYMMDD" (ignore other collections e.g. "docsite-test")

b) Accessing the latest collection:
Adds a step in the Search Docsite service to get the names of collections within an index, and use the collection with the latest date, unless a specific collection is not requested. This is done in _get_most_recent_namespace in DocsiteSearch.
When called from the AI assistant, this would run every time we query the database (once at the beginning of a conversation).

AI Usage

Please disclose how you've used AI in this work (it's cool, we just want to know!):

• Code generation (copilot but not intellisense)
• Learning or fact checking
• Strategy / design
• Optimisation / refactoring
• Translation / spellchecking / doc gen
• Other
• I have not used AI

You can read more details in our Responsible AI Policy