Migrate custom error trait impls to thiserror (#1856)

* Migrate to thiserror

* missing bits

* review comment

* Apply suggestions from code review

Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>

* From<scale_decode::visitor::Error> to remove Into::intos

* scale crates for core::error::Error

* bump msrv 1.81

* make signer crate compile

---------

Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>
Co-authored-by: James Wilson <james.wilson@parity.io>

core/Cargo.toml

@@ -19,10 +19,6 @@ default = ["std"]
 std = [
     "codec/std",
     "scale-info/std",
-    "scale-value/std",
-    "scale-bits/std",
-    "scale-decode/std",
-    "scale-encode/std",
     "frame-metadata/std",
     "subxt-metadata/std",
     "hex/std",
@@ -49,6 +45,8 @@ hex = { workspace = true, default-features = false, features = ["alloc"] }
 serde = { workspace = true, default-features = false, features = ["derive"] }
 serde_json = { workspace = true, default-features = false, features = ["raw_value", "alloc"] }
 hashbrown = { workspace = true }
+thiserror = { workspace = true, default-features = false }
+
 
 # For ss58 encoding AccountId32 to serialize them properly:
 base58 = { workspace = true }
@@ -82,4 +80,4 @@ rustdoc-args = ["--cfg", "docsrs"]
 default-features = true
 
 [lints]
-workspace = true
+workspace = true