Partial implemention of Vector Search

[bmeike]

Includes some tests and a previous commit that fixes some old tests

This is work in progress. Many of the methods are incomplete.

[borrrden]

Ended up with more comments than I thought

[pasin]

Do we release the vector search extension for android as an AAR on a maven server or a downloadable zip file containing .so files?

If we are doing AAR on a maven server, I understand that users will use the vector search like below.

implementation 'com.couchbase.lite:couchbase-lite-android-ee:3.2.0'
implementation 'com.couchbase.lite:couchbase-lite-vector-search-extension:1.0.0'

This would mean that the location of the vector search binary will be where the Android OS put the Native libraries for the application. So I'm not sure if there will be cases that user will customize the location beside using the default location.

[bmeike]

@pasin That is totally your call. If we don't expose a path for the VS lib, things get a lot easier.

[bmeike]

Changed to remove client specified extension path