cherry pick pd refactor for ncs 3.1 branch#501

bjarki-andreasen merged 4 commits intonrfconnect:ncs-v3.1-branchnrfconnect/sdk-mcuboot:ncs-v3.1-branchfrom

bjarki-andreasen:ncs-v3.1-pd-refactorbjarki-andreasen/sdk-mcuboot:ncs-v3.1-pd-refactorCopy head branch name to clipboard