This PS introduces phase plan for CAPD provider
* Adds phase to merge kubeconfig
* Patches type/gating plan to use capd phase plan
* Patches cluster_map and executor to work with "default" namespace
* Fixes CAPD zuul failures
Relates-To: #564
Relates-To: #580
Relates-To: #587
Change-Id: I5007970c907bc87dccf6dd9fcb052afc1b5c13f7