Port from 0.13: Create a new HD seed after encrypting the wallet
Forward-ports two commits from 0.13:
- [0.13] Create a new HD seed after encrypting the wallet
- [Wallet] Add CKeyMetadata record for HDMasterKey(s), factor out HD key generation
Github-Pull: #8389
Rebased-From: f142c11ac634df487cc4bc65a5f1c9a3e3563dd9 de45c065f0648c4c41b57cb492420ceeed29dd11