Refactor getModulePath and fix decorator errors

[keturiosakys]

This PR fixes several issues:

• Decorators were throwing out this values for the methods they were wrapping. Core wrapper autometrics now uses Function.apply to preserve the this context.
• Using Function.apply also doesn't require copying all of the parameters using the spread operator which should reduce memory footprint for functions that have large parameter objects they're passing around.
• Refactors getModulePath utility: it now constructs a custom stack trace with only the necessary information to get the filename without string parsing.

It also adds a test to ensure decorators work properly.

[flenter]

🎉 nice