Merge bitcoindevkit/bdk#713: Add datatype for is_spent sqlite column

54d768412abf218d2646aba211bb79b9dd287118 Sqlite migrations should either succeed or fail (Vladimir Fomene)
369e17b8012df56587c10cd9ce6651908d6a4be9 Add datatype for is_spent sqlite column (Vladimir Fomene)

Pull request description:

  ### Description

  During table creation, Sqlite does not throw an error when a column datatype is not defined. In addition, the datatype provided during table creation does not put a constraint on the type of data that can be put in that column. So you can easily put a string value in an integer column. Despite this, I think it is important for us to add the datatype for clarity.

  ### Notes to the reviewers

  You can read more about how Sqlite dynamic typing [here](https://www.sqlite.org/faq.html). I have amended our `migrate` code with a new commit. The idea is to run migrations in a transaction so that they either succeed or fail. This prevents us from having the database in an inconsistent state at any point in time.

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

  #### Bugfixes:

  * [ ] This pull request breaks the existing API
  * [ ] I've added tests to reproduce the issue which are now passing
  * [ ] I'm linking the issue being fixed by this PR

ACKs for top commit:
  rajarshimaitra:
    tACK 54d768412abf218d2646aba211bb79b9dd287118
  afilini:
    ACK 54d768412abf218d2646aba211bb79b9dd287118

Tree-SHA512: bb6c0467f799ca917f8d45c6495b766352b3177fc81952fcdd678208abf092fdeae966686528a5dcb3f342d7171783274df6312a08cbef3580063e059f5f7254

diff --cc src/database/sqlite.rs
Simple merge