When performing a schema change through group 0, extend the schema mutations with a version that's persisted and then used by the nodes in the cluster in place of the old schema digest, which becomes horribly slow as we perform more and more schema changes (#7620).
If the change is a table create or alter, also extend the mutations with a version for this table to be used for `schema::version()`s instead of having each node calculate a hash which is susceptible to bugs (#13957).
When performing a schema change in Raft RECOVERY mode we also extend schema mutations which forces nodes to revert to the old way of calculating schema versions when necessary.
We can only introduce these extensions if all of the cluster understands them, so protect this code by a new cluster/schema feature, `GROUP0_SCHEMA_VERSIONING`.
Fixes: #7620Fixes: #13957Closesscylladb/scylladb#15331
* github.com:scylladb/scylladb:
test: add test for group 0 schema versioning
test/pylib: log_browsing: fix type hint
feature_service: enable `GROUP0_SCHEMA_VERSIONING` in Raft mode
schema_tables: don't delete `version` cell from `scylla_tables` mutations from group 0
migration_manager: add `committed_by_group0` flag to `system.scylla_tables` mutations
schema_tables: use schema version from group 0 if present
migration_manager: store `group0_schema_version` in `scylla_local` during schema changes
migration_manager: migration_request handler: assume `canonical_mutation` support
system_keyspace: make `get/set_scylla_local_param` public
feature_service: add `GROUP0_SCHEMA_VERSIONING` feature
schema_tables: refactor `scylla_tables(schema_features)`
migration_manager: add `std::move` to avoid a copy
schema_tables: remove default value for `reload` in `merge_schema`
schema_tables: pass `reload` flag when calling `merge_schema` cross-shard
system_keyspace: fix outdated comment
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