Description

A batch of changes to the schema making use of inheritance, input parameters and summaries. These aim to mean we can have more control over search without requiring schema changes in future. Recommended that the easiest way to go through this PR is by commit.

Change since reviews of the draft PR: you can now add a custom request body in SearchParameters, which gives us full control over the SearchAdaptor without having to push field changes through the schema and then pydantic models, and more immediately gives us control over the weightings of individual query components. I've demonstrated this in a test which shows that setting the closeness features to 0 is the same as using the hybrid_no_closeness rank profile.

Also:

• set document languages to english
• adds text fields with _bolding suffixes which give the bolded version of each when a search is done this didn't work, so have deleted it from this PR
• adds a new hybrid profile with nativeRank - Vespa's alternative to BM25 that gives you a little bit more control and produces normalised scores

Sidenote: I tried to test this on the backend using the test pypi published package from this PR's CI but the Vespa dependency seemed to be broken on that. Not sure whether this is just me or it's actually broken 🤷

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