Add custom CI to run mutation testing completely manually by users from a given team

[ASuciuX]

This PR:

• uses the custom workflow dispatch in order to know that the mutants should be run even if the number is above the selected thresholds for one or more packages
• adds an action to check if a given user is part of the selected team
• will not run if the person calling the mutants manual dispatch is not part of the wanted team

Will only be merged after the master PR gets merged as that is required for testing stacks-network/stacks-core#5082.