Merge bitcoindevkit/bdk#535: Remove blockchain from wallet

0cc4700bd67be84bb5cb0814bf5c8aa9fc3f3cdc Fix typo in CHANGELOG and doc in wallet/mod.rs (Steve Myers)
660faab1e20defe86a7baf132e52928f538b9cbb Fix typo in CHANGELOG (LLFourn)
45767fcaf7c65d5020f99fdc35c147acd6e8d037 Remove max_addresses sync param (LLFourn)
fbb50ad1c886a9cb716146fa823558d7d655c7b7 apply doc suggestions from @notmandatory (Lloyd Fournier)
035307ef54ebc330b1760bbdd17bdab3b167cfeb [rpc] Filter out unrelated transactions (LLFourn)
c0e75fc1a8560cdacf705ff60ef8833befd8280c Split get_tx into its own trait (LLFourn)
dcd90f8b61287164dae60f039848d3605eab8616 Restore but depreciate new_offline (LLFourn)
410a51355bb47dbf3401cbe6f19546255c6721e0 Add SyncOptions as the second argument to Wallet::sync (LLFourn)
326bfe82a89eaa79acf90c34442234c7e53e1caf Remove Blockchain from wallet (LLFourn)

Pull request description:

  While trying to finish #490 I thought that it'd be better to try the idea of getting rid of a lot of the async macros and just having tow different traits for sync and async stuff. While trying to do that I felt that this needed to be done first.

  The goal of this change is to decouple the wallet from the blockchain trait. A wallet is something that keeps track of UTXOs and transactions (and can sign things). The only reason it should need to talk to the blockchain is if doing a `sync`. So we remove all superfluous calls to the blockchain and precisely define the requirements for the blockchain to be used to sync with two new traits: `WalletSync` and `GetHeight`.

  1. Stop requesting height when wallet is created
  2. `new_offline` is just `new` now.
  3. a `WalletSync + GetHeight` is now the first argument to `sync`.
  4. `SyncOptions` replaces the existing options to `sync` and allows for less friction when making breaking changes in the fuutre (no more noop_progress!).
  5. We `Box` the `Progress` now to avoid type parameters
  6. broadcast has been removed from `Wallet`. You just use the blockchain directly to broadcast now.

  ### Notes to the reviewers

  This needs #502 before it can be merged but can reviewed now.
  Be on the look up for stale documentation from this change.
  Our doc build looks broken because of ureq or something.

  ### 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
  * [x] I've updated `CHANGELOG.md`

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Tree-SHA512: a8f3e21e45359be642b1f30d4ac1ba74785439e1b770dbeab0a5a4b8aab1eef4bb6b855aea4382e289257bc890fa713ca832a8b6c9655f7a59e96d412b4da3e6