- fix username handling regression introduced in v0.2.0

- make number normalization independent of the PBX' No.Type field.

- we now attempt to normalize PBX numbers to E123 before sending to Zammad.
- relatedly: refactor TrimFirstZero option into TrunkPrefix. Earlier behaviour truncated the hardcoded string "0" from numbers, now this is configurable.

Other changes:
- be more verbose about zammad submission status
- update PBX WSDL to v11

- wait for current calls to terminate before exiting

- use "nohide" when searching for users during group filtering
- humanize representation of GroupCacheTime in metrics

- add --version option
- build releases with version info
- convert user search to Cn instead of e164
  this should solve issues with users with custom "caller-id" number
- change confpath default to /etc
- remove confpath short variant

Just minor release fix

We now only lock the specific call entry during Submit(), reducing
contention on global call map.
Additionally, we generate a UUID for each handled call to ensure
uniquenes on Zammad's side.