Add "clean" command

[patinthehat]

This PR borrows and extends code from spatie/ray to implement a rector/rector rule for removing calls to ray(), rd(), Ray::* and ->ray().

It adds a clean subcommand to the x-ray command:

x-ray clean <path> [--dry-run]

The clean command uses rector to remove references to the functions/methods listed above. In the original spatie/ray code, some of the possible functions/methods weren't accounted for; this PR updates the code to account for all possible ray references.

This PR also bumps several dependency versions, drops support for PHP versions below 8.1 and drops symfony/* support for versions below 6.x. As such, a new major version release is likely best for releasing the functionality in this PR.

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The ultimate objective for this PR is to remove the related functionality from spatie/ray to keep concerns separate; I believe that this functionality belongs in the spatie/x-ray package instead of the spatie/ray package. The ray package should only contain functionality related to Ray, in our opinion.

ping @freekmurze - any thoughts on this?

[freekmurze]

Looks good to me, but still want to keep it in the ray package as well, so people don't need to install an extra dependency to be able to use this.

[patinthehat]

@freekmurze Thanks! I'll open a PR on spatie/ray with the rector code updates I added.