[ui] Add/Edit service chart values

[richard-cox]

• To flesh out, but the UI side of Allow setting service chart values with CLI epinio#1633
• It's expected these work in the same way as application chart values

### Tasks
- [ ] https://github.com/epinio/ui/issues/338
- [ ] https://github.com/epinio/ui/issues/339
- [ ] https://github.com/epinio/ui/issues/302

[richard-cox]

See epinio/epinio#1633 (comment)