Change names of certain script files by adding _main suffix to them to avoid outdated addons from causing issues

[Nesciuse]

Suggestion

director_base.nut
scriptedmode.nut
resposne_testbed.nut
mapspawn.nut

In context of using these in addons they've been pretty much on their deprecated period since the TLS update added their special _addon suffixed version. What should be done is adding _main suffix to all of these to prevent issues caused by outdated addons that are still using these instead of _addon version. This would also prevent some potential false bug reports. Don't think there is a single addon that actually requires using those files and if there is they will simply have to change their name by adding _main suffix to them. This suggestion would require Valve to do it changing the code to search for _main suffixed version of those files.