Better address setup

[afilini]

Description

Instead of using the derivation index we should store for each address whether or not it has been "setup" with the blockchain backend. We could merge Blockchain::setup() with Blockchain::sync() and just let the function decide what to do with each address based on its status.

Probably depends on #359 since we would have to change the db interface.

Expected Outcomes

• Update blockchain module traits and structs as needed and fix corresponding tests
• Add add or combine tests if needed to cover updated functionality
• Update any modified public traits and structs documentation

Resources

• BDK Website
• BDK github repo
• BDK Discord

Skills Required

• Experience with git. Guide
• Basic familiarity with rust. First seven chapters of the book
• Familiarity with bitcoin descriptors and address generation
• Familiarity with changes made for schema migration in Handle database migrations #359

Mentor(s)
@notmandatory

Difficulty
Medium

Competency Test

• Install rust, compile and run all bdk examples and tests.
• Read through the BDK docs.
• Make a dummy wallet with BDK with key-value and sqlite backends.
• Familiarity with basic rust, should be able to write basic custom trait implementations on foreign structures.