stdlib: Add a TOML library

[spotandjake]

In grain v0.6.0 we added support for parsing, Json I think we should also support TOML in the stdlib. I implemented a mostly complete parser here: https://github.com/spotandjake/Grain-Toml which is a good base for a library but it will need some refactoring and will need to be finished, this also is geared to support TOML v1.1.0 which is the next release version. whereas we probably want to support TOML v1.0.0 which is the current release.

On another related note given we already have a few parsing libraries and will likely want to add more if we want to support more things like TOML or YAML it might make sense to implement a low level parsing library in the stdlib, this will have the benefits of standardizing the way we write parsers between utilities like json and url decoding currently.