40f9dd9bc43bac0c966585ac2770a02aa4c92765 replace the descriptor by template + key vector in descriptor registration step (pythcoiner) Pull request description: This PR replace the descriptor displayed in the installer descriptor registration step, by the wallet policies template + its keys, as almost (all?) signing devices displays the discriptor in this way for registration.  closes #727 ACKs for top commit: jp1ac4: Tested ACK 40f9dd9bc43bac0c966585ac2770a02aa4c92765. Tree-SHA512: 396d20d766b89b93d3f598b3168311dfa693fcd83efe02e0515ee6428e006a5e2db4f502e3b21f50a085f37e44a1049bbfa3e4e09719a6101396012b80486cea