feat: Support FormData object entries parsing

[mdoury]

Here is a solution to support object entries in FormData which enables <input type="file" /> parsing.

FormData object entries are stringified before FormData is parsed using the URLSearchParams trick.

FormData object entries are not parsed by the default parser, making it rather versatile as it enables users to parse object entries of any type using a custom parser.

I had to make some typings generic in order to support custom parsed search params types.

Fixes #14.

[rileytomasek]

Thank you! Looks good from a quick read — I'll do a proper review and merge+release tomorrow because I assume you need this for your project.

[mdoury]

Thank you, that'd be great!

[rileytomasek]

Thanks again for adding this, @mdoury. I just published it as v0.3.1.

[mdoury]

You're welcome @rileytomasek. I'd be happy to help more if you want.

[rileytomasek]

Thanks @mdoury. Let me know if you have any ideas, but I'd like to keep Zodix as lean as possible, and prevent it from evolving into another of the many bloated form libraries.