Add support custom field types to form config and pydantic model

[signebedi]

We should add support for a hidden field, as well as maybe the following:

1. immutable_user_field - shows some unchangeable field pulled from the current user's data
2. user_list - list of current users, ordered alphabetically, with some selected field from the data model (id, username, email seem most likely). Maybe allow to select by group?
3. resizable_textarea - maybe we just set this as the default behavior for textarea fields...
4. autoselect - allows users to begin typing their answer and have it filled automatically.
5. bool_switch - allows users to toggle value between true/false (or yes/no)

[signebedi]

Add support for database queries and callables as form backends
This is potentially very complex. Sometimes, a select, radio, or checkbox field will want to draw its options from a callable or database query. This can be a little finicky, so we'll approach it gradually.

[signebedi]

We've implemented the better part of these features in #150 and elsewhere. However, the following still need implementation.

hidden field - we should also add options to make_visible_in_edits and secondary_input_type
immutable_user_field - shows some unchangeable field pulled from the current user's data
bool_switch - allows users to toggle value between true/false (or yes/no)

[signebedi]

Add hidden field input types
We should also add options to make_visible_in_edits and secondary_input_type

[signebedi]

Add immutable_user_field field input types
Shows some unchangeable field pulled from the current user's data, like their groups, username, relationships, etc.

[signebedi]

Add bool_switch field input types
Allows users to toggle value between true/false (or yes/no). Maybe we add a true_label and false_label option if end users want to mask these for the end user.