[WIP] Show better errors for collaborative deployment scenarios

[lennartkats-db]

Changes

This adds diagnostics for collaborative (production) deployment scenarios, including:

• Bob deploys a bundle that is normally deployed by Alice, but this fails because Bob can't write to /Users/Alice/.bundle.
• Charlie deploys a bundle that is normally deployed by Alice, but this fails because he can't create a new pipeline where Alice would be the owner.
• Alice deploys a bundle where she didn't list herself as one of the CAN_MANAGE users in permissions. That can work, but is probably a mistake.

Tests

Unit tests, manual testing.