Adding in Event Filter plugin

[marshvee]

Add a plugin to be able to filter events based on their name.

We have a particular case, we want to keep using autocapture events (to get pageleave and pageview events) but we don't want the usual $autocapture (clicks, interactions, etc), so we can't just turn off autocapture from the app config.

[yakkomajuri]

Hey @marshvee! Could you submit this to https://github.com/PostHog/integrations-repository instead?