Make location field non-required

[elchupanebrej]

🤔 What's the problem you're trying to solve?

At https://github.com/elchupanebrej/pytest-bdd-ng there is a possibility to store features in formats different from .gherkin or .md files (yaml, ndjson, toml, etc.). Third-party parsers of these formats do not always give information about consumed tokens, so it's not possible to put correct values to the Location field

✨ What's your proposed solution?

• Make the Location field non-required, so it won't be filled if the parser doesn't grant needed information.
• Add the possibility to add custom mime types into MediaType schema