allow creating routes with grades other than YDS, V, Font, French

[musoke]

What would you like to be able to do? Please describe.

I would like to create a boulder problem at https://openbeta.io/crag/ba6e3321-6311-5aed-ae4a-48eede31fc9c

This is not possible right now, as open tacos doesn't seem to know how to parse the grades other than YDS, V, Font, French.

How important is this to you (Please pick one)

• Critical

Currently most of the world not only has no routes, it's impossible to create them.

[musoke]

Tracking blocking issues:

• move contexts from openbeta-graphql to sandbag sandbag#125
• Get definitions of grade contexts from library #797