This makes it possible to remove remaining users of the global qctx.
The thing is that db::schema_tables code needs to get wasm's engine, alien runner and instance cache to build wasm context for the merged function or to drop it from cache in the opposite case. To get the wasm stuff, this code uses global qctx -> query_processor -> wasm chain. However, the functions (un)merging code already has the database reference at hand, and its natural to get wasm stuff from it, not from the q.p. which is not available
So this PR packs the wasm engine, runner and cache on sharded<wasm::manager> instance, makes the manager be referenced by both q.p. and database and removes the qctx from schema tables code
Closes#14933
* github.com:scylladb/scylladb:
schema_tables: Stop using qctx
database: Add wasm::manager& dependency
main, cql_test_env, wasm: Start wasm::manager earlier
wasm: Shuffle context::context()
wasm: Add manager::remove()
wasm: Add manager::precompile()
wasm: Move stop() out of query_processor
wasm: Make wasm sharded<manager>
query_processor: Wrap wasm stuff in a struct
6c1e44e237