pallet-treasury: Ensure we respect max_amount for spend across batch calls (#13468)

* `pallet-treasury`: Ensure we respect `max_amount` for spend across batch calls

When calling `spend` the origin defines the `max_amount` of tokens it is allowed to spend. The
problem is that someone can send a `batch(spend, spend)` to circumvent this restriction as we don't
check across different calls that the `max_amount` is respected. This pull request fixes this
behavior by introducing a so-called dispatch context. This dispatch context is created once per
outer most `dispatch` call. For more information see the docs in this pr. The treasury then uses
this dispatch context to attach information about already spent funds per `max_amount` (we assume
that each origin has a different `max_amount` configured). So, a `batch(spend, spend)` is now
checked to stay inside the allowed spending bounds.

Fixes: https://github.com/paritytech/substrate/issues/13167

* Import `Box` for wasm

* FMT

substrate/frame/support/Cargo.toml

@@ -38,6 +38,7 @@ smallvec = "1.8.0"
 log = { version = "0.4.17", default-features = false }
 sp-core-hashing-proc-macro = { version = "5.0.0", path = "../../primitives/core/hashing/proc-macro" }
 k256 = { version = "0.11.5", default-features = false, features = ["ecdsa"] }
+environmental = { version = "1.1.4", default-features = false }
 
 [dev-dependencies]
 serde_json = "1.0.85"
@@ -67,6 +68,7 @@ std = [
 	"sp-weights/std",
 	"frame-support-procedural/std",
 	"log/std",
+	"environmental/std",
 ]
 runtime-benchmarks = []
 try-runtime = []