Add edit CRM contact UI

What does this MR do and why?

Related to #2256

Adds the ability to edit CRM contacts from the UI.

Screenshots or screen recordings

How to set up and validate locally

Now we've added seed data, this is much easier 🎉

1. If you've not recently setup GDK or run `gdk reset-data`, you'll need to run the crm seed: `rake db:seed_fu FILTER=crm`
2. Enable the `customer_relations` feature flag from the rails console: `Feature.enable(:customer_relations)`
3. Navigate to a group contacts page- e.g. http://gdk.test:3000/groups/flightjs/-/crm/contacts
4. Click the edit button alongside one of the contacts
5. Modify one or more contact fields
6. Click save changes

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.