Contacts: add sending address book create, edit, and delete flow

[johnny9]

Gap

QML only exposes receive and change addresses. It skips non-RECEIVE wallet address-book entries, so there is no equivalent to the Qt sending address book for contacts.

Work

Add a contact/sending-address model and UI path for creating, editing, deleting, copying, and viewing SEND address-book entries. Preserve receive/change address behavior and keep labels synchronized with the wallet address book.

Code References

• qml/models/addresslistmodel.cpp:224
• bitcoin/src/qt/addresstablemodel.cpp:349
• bitcoin/src/qt/addressbookpage.cpp:179