Echo hook BeforeCreateEchoEvent is triggered very early in
Setup.php. This causes all dependencies of Thanks/Hooks to be
initialized. One of the places that is affected is the `addWiki.php`
script that tries to redefine the RevisionStore service, but cannot
due to fact it's already initialized.
Both Echo hooks (BeforeCreateEchoEvent and EchoGetBundleRules) do
not require any dependencies, and due to fact that one of those is
initialized early, let's move them to a separate small EchoHooks
class that would handle Echo specific logic.
Bug: T358236
Change-Id: I0e348872ba5dc313325e3f4f296fd84bfb2c785b
