Remove Media hooks

[aldeed]

Search for MediaRecords.before. in /imports/plugins/core/revisions/server/hooks.js and remove those hooks, but keep the revision control that they implement.

For inserts

The only Media.insert that needs revision control is in /imports/plugins/core/ui/client/containers/mediaGallery.js

Move that insert to a Meteor method, and move the MediaRecords.before.insert logic into that method.

For updates

Make an "updateMediaMetadata" method to replace MediaRecords.before.update.

Needs to be called in one place: /imports/plugins/core/files/server/methods.js in the sortedMediaIDs.forEach

For removes

Make a "removeMedia" method to replace MediaRecords.before.remove.

Call "removeMedia" method instead of Media.remove directly in /imports/plugins/core/ui/client/containers/mediaGallery.js

Should be able to fix #3992 while doing this.