Remove "native script" errors for Skyrim game

[KrisV-777]

I dont know when exactly "native scripts" became a thing or if it something Caprica specific (in which case, pardon this PR), but at least for Skyrim the "native" keyword exclusively belongs to function definitions, there is no such thing as a "native script"

These are a handful of changes to skip "native script" related checks for Skyrim only, in particular

• new event definitions only throw a warning, the CLI argument has been removed (as new event definitions are perfectly valid and a common praxis when using script extenders, including SKSE itself)
• native function definitions on "non native scripts" no longer throw an error, as all of Skyrim's scripts are "non native" and adding "native" to a script definition would throw an error by Bethesdas compiler

Additionally, I made a small change to the workflow which had a depreciated error before