* AlloyDB read poll support and various usability fixes
* Added support for read poll instances.
* Added support for public (outbound) IPs.
* Added new arguments: `machine_type`, `skip_await_major_version_upgrade`, and `subscription_type`.
* Added outputs for key cluster attributes, including ID and name.
* Improved input variable validations and simplified configurations.
* Fixed bug where AlloyDB user accounts always had null passwords.
* Resolved Terraform state drift issues for `network_config` and `psc_config`.
* Fixed `continuous_backup_config` always being implicitly or explicitly enabled.
* Fixed `automated_backup_policy` and `maintenance_update_policy`, which do not support non-zero minutes, seconds and nanos.
* Fixed various typos.
* Aligned the format of test examples.
* Fixed invalid condition: authorized external networks require enabled public IP, however enabled public IP can have empty authorized external networks
* Formatting
* Fix PSA block
---------
Co-authored-by: Julio Castillo <jccb@google.com>
