Mock ViolentMonkey injection on GreasyFork

Mocks ViolentMonkey's injection into GreasyFork:

Removes prompt to install a script manager
Greasyfork will now dynamically change the install button:
- Show the standard install button if the user hasn't installed the script
- Show Update to version ${versionString} when the remote version is more up-to-date than the installed version
- Show Reinstall version ${versionString} when the remote version matches the installed version

Currently ignores the namespace, since PDA script names must be unique.

Screenshot of the Reinstall Version button

Manuito83 / torn-pda