Make sp_core and sp_runtime dependencies optional, and bump to latest (#760)

* begin porting over traits; remove Config use of Hash

* port over the Header bits that we need

* sp_core_hashing where possible, move Verify to PairSigner, remove unused errors

* tidy up Config things and move related bits into one place

* fix codegen

* copy Era over

* move AccountId, Address, Signer to Signer trait and a pass over fixing examples

* impl MultiAddress, MultiSignature, AccountId32 and add back to Config (for decoding later)

* Copy over StorageKey, StorageData, StorageChangeSet

* subxt core compiling with no sp_core or sp_runtime

* Get examples compiling

* pass over fixing tests

* cargo fmt

* clippy tweaks and update polkadot.rs

* fix codegen docs

* port over special DigestItem encoding/decoding

* clippy and doc fixes

* cargo fmt and example fix

* more cargo fmt-ing...

* substrate-extra to substrate-compat

* cargo.toml comments

* simplify PairSigner trait bounds

* move RPC types to a separate file

* fix docs

* Add some tests for things and other PR feedback

* bump to latest sp deps

* avoid needing substrate-compat feature in a test

subxt/src/error.rs

@@ -19,8 +19,6 @@ pub use scale_value::scale::{
     DecodeError,
     EncodeError,
 };
-pub use sp_core::crypto::SecretStringError;
-pub use sp_runtime::transaction_validity::TransactionValidityError;
 
 /// The underlying error enum, generic over the type held by the `Runtime`
 /// variant. Prefer to use the [`Error<E>`] and [`Error`] aliases over
@@ -39,12 +37,6 @@ pub enum Error {
     /// Serde serialization error
     #[error("Serde json error: {0}")]
     Serialization(#[from] serde_json::error::Error),
-    /// Secret string error.
-    #[error("Secret String Error")]
-    SecretString(SecretStringError),
-    /// Extrinsic validity error
-    #[error("Transaction Validity Error: {0:?}")]
-    Invalid(TransactionValidityError),
     /// Invalid metadata error
     #[error("Invalid Metadata: {0}")]
     InvalidMetadata(#[from] InvalidMetadataError),
@@ -74,18 +66,6 @@ pub enum Error {
     Other(String),
 }
 
-impl From<SecretStringError> for Error {
-    fn from(error: SecretStringError) -> Self {
-        Error::SecretString(error)
-    }
-}
-
-impl From<TransactionValidityError> for Error {
-    fn from(error: TransactionValidityError) -> Self {
-        Error::Invalid(error)
-    }
-}
-
 impl From<&str> for Error {
     fn from(error: &str) -> Self {
         Error::Other(error.into())