The ctxt object is used to carry necessary context around schema
unfreezing. It collects some information it needs from
replica::database::get_config(), thus generating unwanted dependency on
global db::config. This PR make ctxt be created by the database itself
(and by tests) ,thus eliminating one more dependency on large global
db::config
Cleaning components dependencies, not backporting
Closesscylladb/scylladb#30186
* github.com:scylladb/scylladb:
db/schema_tables: Remove schema_ctxt convenience constructors
db/schema_tables: Use get_schema_ctxt() in callers
replica/database: Introduce get_schema_ctxt() method
db/schema_tables: Replace config& with individual fields in schema_ctxt constructor
ecad28915f