Initial support for vespa search

[joel-wright]

Description

Support for optionally using a configured vespa instance for search.

Type of change

Please select the option(s) below that are most relevant:

• Bug fix
• New feature
• Breaking change

How Has This Been Tested?

New tests added & test vespa instance added to docker compose environment.

Reviewer Checklist

• The PR represents a single feature (small driveby fixes are also ok)
• The PR includes tests that are sufficient for the level of risk
• The code is sufficiently commented, particularly in hard-to-understand areas
• Any required documentation updates have been made
• Any TODOs added are captured in future tickets
• No FIXMEs remain

[diversemix]

looking good so far - is it meant to be still draft?

[diversemix]

Tests look good - we perhaps need to chat about cpr_data_access and the models contained therein. Just to fully understand what the intention is and the future of this is.