Added some CLI change handling to prevent errors

Added some CLI change handling to prevent errors

Added proper detection of CLI changes, with early quite and output to
tell user to re-run, instead of erroring with a stack trace.
Used in scenario where the CLI will change itself as part of BookStack
updates.

Toyed with the idea of pre-compiling CLI PHP files, or handling the
scenario to switch to the new CLI version, but those are a lot more
complex and potentially error prone.