lsps: Implement the transport layer for lsps0

For lsps0 we send JSON-RPC messages via custom messages over the
lightning network. This commit adds a basic implementation based
on custom messages.

Cargo.lock

@@ -419,8 +419,10 @@ dependencies = [
 name = "cln-lsps"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "async-trait",
- "dashmap",
+ "cln-plugin",
+ "cln-rpc",
  "hex",
  "log",
  "rand 0.9.1",
@@ -526,20 +528,6 @@ dependencies = [
  "typenum",
 ]
 
-[[package]]
-name = "dashmap"
-version = "6.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5041cc499144891f3790297212f32a74fb938e5136a14943f338ef9e0ae276cf"
-dependencies = [
- "cfg-if",
- "crossbeam-utils",
- "hashbrown 0.14.5",
- "lock_api",
- "once_cell",
- "parking_lot_core",
-]
-
 [[package]]
 name = "data-encoding"
 version = "2.7.0"
@@ -872,12 +860,6 @@ version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
 
-[[package]]
-name = "hashbrown"
-version = "0.14.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
-
 [[package]]
 name = "hashbrown"
 version = "0.15.2"