feat: implement a request cache for mutation and insertion queries

[fengelniederhammer]

Also make sure to invalidate the cache when SILO has a new data version

resolves #137

PR Checklist

• [ ] All necessary documentation has been adapted.
• The implemented feature is covered by an appropriate test.

[chaoran-chen]

@fengelniederhammer, it just came to my mind (in case you haven't considered it already): if the query asks for a random order, the result may not be cached.

[fengelniederhammer]

Thanks for the reminder! I added a comment to #658

[JonasKellerer]

Can we somehow test whether the cache is invalidated when a new data version is available?

Also do we need to add some docu?

[fengelniederhammer]

There is SiloClientAndCacheInvalidatorTest in SiloClientTest.kt that checks tests this: populate the cache with some data version, set the SILO mock to return a new data version and check that the next time, the cache isn't hit.

I'll do the docs in a separate PR.