Set dynamic file output name

[spinillos]

Cogs allows to define a destination path, but the final path depends of the language. For example, Go set the tyoes under 'pkg'/types_gen.go and TS under src/'pkg'/types_gen.ts.

It could be nice if we can define output name completely.

Changing the output for these files could affect to the imports that points to cog tooling generated to make the code works (Variants, Runtime, JSONMarshalling, etc...)