feat(electrum)!: use new sync/full-scan structs for ElectrumExt

`ElectrumResultExt` trait is also introduced that adds methods which can
convert the `Anchor` type for the update `TxGraph`.

We also make use of the new `TxCache` fields in
`SyncRequest`/`FullScanRequest`. This way, we can avoid re-fetching full
transactions from Electrum if not needed.

Examples and tests are updated to use the new `ElectrumExt` API.

Author: evanlinjin

crates/electrum/Cargo.toml

@@ -12,7 +12,7 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bdk_chain = { path = "../chain", version = "0.13.0", default-features = false }
+bdk_chain = { path = "../chain", version = "0.13.0" }
 electrum-client = { version = "0.19" }
 #rustls = { version = "=0.21.1", optional = true, features = ["dangerous_configuration"] }