feat: pick up enigmaMockerOptions from fixture

[veinfors]

Makes it possible to pass in options to enigmaMocker even when using it indirectly through nebula serve by picking up enigmaMockerOptions from the root of the fixture.

[DanielS-Qlik]

Maybe add a note about it in this example:

nebula.js/commands/serve/docs/fixture-format.md

Line 76 in 1ac8a87

Generic objects to render visualization with. The objects are used as input to `EnigmaMocker` to base mock upon. See `@nebula.js/enigma-mocker` for more details.

[veinfors]

Maybe add a note about it in this example:

nebula.js/commands/serve/docs/fixture-format.md

Line 76 in 1ac8a87

Generic objects to render visualization with. The objects are used as input to `EnigmaMocker` to base mock upon. See `@nebula.js/enigma-mocker` for more details.

Good point, did that!