RUP form should have a conditions section

**As a** *Decision Maker* **I want** *to have a conditions section on the plan form* **So That** *I can provide conditions for an RUP when making a decision*.

**Additional Context**
- Will probably just be a text field at the top of the form
- Should only be editable in the statuses where DM can make a decision
- Another column will have to be added to the `plan` table. I'm not going to track that in the API repo since it's a pretty minor change.

**Acceptance Criteria**
- [ ] Only DM can write conditions
- [ ] Still works with versioning