Rework GraduatedRebalancer to work across restarts

Previously, we would await payment successes before doing a rebalance
successful event. This would cause issues if the app was closed during a
rebalance. This adds handling so the GraduatedRebalancer is now event
based and persists its state. We also now have better handling for
failed rebalances to go along with it.

Author: benthecarman

Cargo.toml

@@ -19,6 +19,7 @@ panic = 'abort'     # Abort on panic
 bitcoin-payment-instructions = { version = "0.6.0" }
 lightning = { version = "0.2.0" }
 lightning-invoice = { version = "0.34.0" }
+lightning-macros = "0.2.0"
 
 [profile.release]
 panic = "abort"

graduated-rebalancer/Cargo.toml

@@ -10,4 +10,5 @@ license = "MIT OR Apache-2.0"
 bitcoin-payment-instructions = { workspace = true }
 lightning = { workspace = true }
 lightning-invoice = { workspace = true }
-tokio = { version = "1", default-features = false }
+lightning-macros = { workspace = true }
+tokio = { version = "1", default-features = false, features = ["sync"] }