Wrapping up datatypes part 1

[madprime]

Description

Opening a PR for my work so it can be reviewed, because I might be impaired by opioid drugs.

Related Issue

Here's a list of TODO items we still want:

• Dropdown in form for submitting/editing datatypes needs to be ordered
• Show "see full list" all the time, not just when there's no parent
• List of DataTypes per project should be filtered on approved projects
• Project setup description/docs need to include guide for registering data types
• 'Manage projects' redesigned to have one "manage project" button & name linked to activity page

Originally posted by @madprime in #1026 (comment)

Testing

• pass automated tests
• manually testing each item locally

[mldulaney]

Only comment, as noted in Slack, is that there is not a way to return to the select datatypes for a project page if one goes to add a datatype.

Otherwise, looks skookum here!