[12.x] Add Expired Flag to cache:clear

[onairmarc]

Overview

This PR adds the --expired flag to the cache:clear artisan command. This is useful because expired cache items are not automatically deleted from the cache table once they have expired.

The main thought behind adding this flag is that cache:clear --expired would be run on a set schedule (i.e. daily) inside of routes/console.php.

Usage

• Running cache:clear --expired will clean up any expired cache items for the DatabaseStore only.
• When the --expired flag is passed, only expired cache items will be removed from the cache table.
• This flag will not affect cache items that have not yet expired.
• If the cache:clear --expired is run on a non-DatabaseStore cache store, the command will run as if --expired was not passed in the first place.

Please let me know if you would like me to make any changes.

Note: An alternative option could be a dedicated command rather than changing behavior based on a flag. If desired, I can make those modifications in this PR.

[taylorotwell]

Thanks for your pull request to Laravel!

Unfortunately, I'm going to delay merging this code for now. To preserve our ability to adequately maintain the framework, we need to be very careful regarding the amount of code we include.

If applicable, please consider releasing your code as a package so that the community can still take advantage of your contributions!