Better no-std support

- Use `default-features = false` for `miniscript`,`bitcoin`,and `bdk_chain`
- Introduce `bdk_chain/std` feature
- Add GitHub workflow `check-no-std` (not yet completly working)
- Update GitHub workflow `check-wasm` to disable default `std` features

crates/chain/Cargo.toml

@@ -13,18 +13,18 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bitcoin = { version = "0.29" }
+bitcoin = { version = "0.29", default-features = false }
 serde_crate = { package = "serde", version = "1", optional = true, features = ["derive"] }
 
 # Use hashbrown as a feature flag to have HashSet and HashMap from it.
 # note version 0.13 breaks outs MSRV.
-hashbrown = { version = "0.12", optional = true,  features = ["serde"] }
-miniscript = { version = "9.0.0", optional = true  }
+hashbrown = { version = "0.12", optional = true, features = ["serde"] }
+miniscript = { version = "9.0.0", optional = true, default-features = false }
 
 [dev-dependencies]
 rand = "0.8"
 
 [features]
-default = ["std", "miniscript"]
-std = []
+default = ["std"]
+std = ["bitcoin/std"]
 serde = ["serde_crate", "bitcoin/serde" ]