Add --rules-summary option to display applied rules summary with count

[carlos-granados]

Adds a new --rules-summary CLI option that displays a summary of all rules applied during a Rector run, showing each rule name and the number of times it was applied (or would have been applied in dry-run mode). The list is sorted, showing the rules which were applied more often at the top. If the command line option is not set, then no summary will be printed by default.

This can be useful in a number of ways. For example:

• To see which rules have been applied more often, so that maybe this can be communicated to the team.
• To see which rules are never applied, to see if maybe they can be removed from the rector set.
• When you are applying some rules that will create a big number of changes, see which rules are applied more often so that maybe you can tackle the rules that you apply in a specific order.
• When a large number of rules are applied, maybe spot a rule that you wouldn't expect to be applied and check if this might be an issue with Rector.
• etc...