This pull request introduces a "synchronous mode" for global views. In this mode, all view updates are applied synchronously as if the view was local.
Marking view as a synchronous one can be done using `CREATE MATERIALIZED VIEW` and `ALTER MATERIALIZED VIEW`. E.g.:
```cql
ALTER MATERIALIZED VIEW ks.v WITH synchronous_updates = true;
```
Marking view as a synchronous one was done using tags (originally used by alternator). No big modifications in the view's code were needed.
Fixes: https://github.com/scylladb/scylla/issues/10545Closes#11013
* github.com:scylladb/scylla:
cql-pytest: extend synchronous mv test with new cases
cql-pytest: allow extra parameters in new_materialized_view
docs: add a paragraph on view synchronous updates
test/boost/cql_query_test: add test setting synchronous updates property
test: cql-pytest: add a test for synchronous mode materialized views
db: view: react to synchronous updates tag
cql3: statements: cf_prop_defs: apply synchronous updates tag
alternator, db: move the tag code to db/tags
cql3: statements: add a synchronous_updates property
cb8a67dc98