feat(lambda-promtail): allow prefix matching for CloudWatch log groups

[demon]

What this PR does / why we need it:

If you have a lot of log groups with similar names this is much easier than listing them all explicitly. Or the bonus feature of just including them all by specifying a prefix of "".

While we're here, introduce the ability to add filter patterns on the subscription to narrow the matched logs as desired.

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[CLAassistant]

All committers have signed the CLA.