Multiple concurrent calls to the same rule don't trigger cooldown

[Luzifer]

As a streamer I want my cooldowns to be honored even though multiple user trigger the same command in the same moment.

At the moment i.e. triggering a !dc+ twice in the same "second" counts two deaths even though there is a 30s cooldown on the !dc+ rule.

The cause for this is the rule only to be sent to cooldown after the execution which takes a moment. To solve this the rule needs to be locked. This lock though should take into account which cooldowns are set on the rule not to lock the rule for all channels if there is a channel-based cooldown on it.