Replace the badge builder form

[abompard]

The Badge Builder form should use WTForms to make it easier to maintain and more standard (such as when the posted fields are not reused on the resulting page).
It should have select boxes where options are limited, such as with the Condition.
It should do the YAML generation in the Jinja2 template instead of python string templating to have better conditionals.

[github-actions]

This issue is stale because it has been open for 60 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 7 days since being marked as stale.

[abompard]

Hey!