Better handling of bootstrap and purge errors

### Is your feature request related to a problem? Please describe.

The bootstrap and purge commands currently fail hard on common errors such as:

- realm is already bootstrapped
- realm does not exist or is not bootstrapped

It would be a better UX if we could ignore these errors via a command line option.

Also, the logged messages do not clearly specify which realm failed. In case many realms were provided to the command, that's confusing.

### Describe the solution you'd like

No more annoying messages.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by locating the bootstrap and purge command entry points and the handling for already-bootstrapped, missing, and unbootstrapped realms. Check how command-line options and per-realm log messages are implemented. Done means an option can ignore these common errors and messages identify the affected realm when multiple realms are supplied.

Written by the indexing model from the issue text.