Release v1.5.1

v. 1.5.1

Switching to endpoint as the only/primary way of specifying databases:

• AstraDBClient tolerates (deprecated, removal in 2.0) id[/region] in get_database
• (internal-use constructors and utilities only accept API Endpoint)
• AstraDBAdmin is the only place where id[/region] will remain an allowed path in 2.0
• all tests adapted to reflect this simplification

Admins: resilience against DevOps responses omitting 'keyspace'/'keyspaces'
AstraDBAdmin: added filters and automatic pagination to [async_]list_databases
Consistent handling of deletedCount=-1 from the API (always returned as-is)
Cursors: alignment and rework:

• states are an enum; state names reworked for clarity (better cursor __repr__)
• _copy and _to_sync methods always return a clean pristine cursor
• "retrieved" property deprecated (removal 2.0). Use consumed.
• "collection" property deprecated (removal 2.0). Use data_source.

Deprecation of all set_caller (=> to be set at constructor-time) (removal in 2.0)
Callers and user-agent string:

• remove RAGStack automatic detection

• Deprecate "caller_name/caller_version" parameters in favour of callers pair list

• (minor) breaking change: passing only one of "caller_name/caller_version" to _copy/with_options will override the whole one-item
  callers pair list
  Repo housekeeping:

• using ruff for imports and formatting (instead of isort+black) by @cbornet

• add ruff rules UP(pyupgrade) by @cbornet

• remove cassio unused dependency