Remove ProcessAPI

[kraleppa]

Currently ProcesAPI is used only in LiveViewDebugAPI and in NodeInspectorSidebarLive for highlighting. The only reason why it is used directly there is the fact that we fetch state of channel from which we take join_ref required to send event via debugged application socket to the browser that triggers highlighting.

When we switch to sending messages via custom websocket we'll be able to remove usage of ProcessAPI there and we'll be able to hide it entirely in LiveViewDebugAPI when LiveView version is lower than 1.1.0