davmail: 4.7.1 -> 4.7.2

Bugfix release, detect Exchange throttling to temporarily block requests and a few Carddav fixes.

EWS:
- EWS: handle Exchange throttling, suspend all requests according to server provided delay
- EWS: send DavMailException instead of authentication exception on EWS not available error

Enhancements:
- 128x128 DavMail icon
- Add a new davmail.httpMaxRedirects setting
- DAV: add a hidden davmail.disableNTLM setting

Carddav:
- Carddav: fix another regression on contact create with empty field
- Carddav: remove email over EWS unit test
- Carddav: fix email address removal over EWS