Backup preparatory step

[pythcoiner]

I open this PR as a mid-step of #1576, as these commits are now ready for review and not likely to change.

This PR:

• Implement export of PSBTs
• Implement export of Descriptor
• Implement export of Labels in BIP-0329 format
• Implement export of PSBTs
• Implement export of Descriptor
• add receive_index and change_index to Daemon.get_info() result
• add get_labels_bip329() to Daemon trait
• implement wallet backup/export feature
• Integrate the exports & backup feature to the settings panel (GUI)
• Integrate the backup feature at wallet descriptor backup step (Installer)

223dae2 depends on this PR on our backend

[pythcoiner]

comment addressed + done some rebase cleanup (clippy not passing between commits)

[pythcoiner]

updated DUMP_LABELS_LIMIT to fit the limit added on backend

[pythcoiner]

added default-features = false to bip329 dependency

[pythcoiner]

Note: I just find out that the modal is not displayed at backup descriptor step in installer, I'm going to fix this

[pythcoiner]

Note: I just find out that the modal is not displayed at backup descriptor step in installer, I'm going to fix this

fixed + added a part of a commit that had "jump forward" in the commit history

[jp1ac4]

As an alternative to adding the ctx parameter to the update() method, could you instead add a context field to BackupDescriptor and use the load_context() method to set its value?

[pythcoiner]

using the actual way we are sure to not forget to update the context imho

[pythcoiner]

The provider UUID and name will also now be saved, in addition to the key UUID and token.

yes will start to rebase

[pythcoiner]

rebased on master + backup providers keys metadata

[pythcoiner]

comments addressed