depends: Remove direct `tokio` dependency

We still depend on it indirectly, but we don't use it directly anymore
since we upstreamed our patch to `metrics-exporter-prometheus`.

`thiserror` is also only used by the wallet tool, so has been reordered
accordingly.

Cargo.lock

@@ -963,7 +963,6 @@ dependencies = [
  "subtle",
  "thiserror",
  "time",
- "tokio",
  "tracing",
  "tracing-appender",
  "tracing-core",

Cargo.toml

@@ -61,17 +61,16 @@ zeroize = "1.4.2"
 ipnet = "2"
 metrics = "0.17"
 metrics-exporter-prometheus = "0.6"
-thiserror = "1"
-tokio = { version = "1.0", features = ["rt", "net", "time", "macros"] }
 
 # Wallet tool
-# (also depends on thiserror, tracing, and tracing-subscriber with "env-filter" and "fmt" features)
+# (also depends on tracing, and tracing-subscriber with "env-filter" and "fmt" features)
 anyhow = "1.0"
 backtrace = "0.3"
 clearscreen = "1.0"
 gumdrop = "0.8"
 rand = "0.8"
 secrecy = "0.8"
+thiserror = "1"
 time = { version = "0.3", features = ["formatting", "macros"] }
 
 [dependencies.tracing-subscriber]