Replace reqwest with hyper in monero-serai

Ensures a connection pool isn't used behind-the-scenes, as necessitated by
authenticated connections.

Cargo.lock

@@ -4884,6 +4884,8 @@ dependencies = [
  "group",
  "hex",
  "hex-literal",
+ "hyper",
+ "hyper-rustls",
  "modular-frost",
  "monero-generators",
  "multiexp",
@@ -4892,7 +4894,6 @@ dependencies = [
  "rand_chacha",
  "rand_core",
  "rand_distr",
- "reqwest",
  "serde",
  "serde_json",
  "sha3",