Make working with nested queries a touch easier (#714)

* First pass adding functions to get blocks and extrinsics

* cargo fmt and cache block events

* prefix block hash with 0x

* pin streams for better ergonomics and add an example of subscribing to blocks

* remove unused var

* standardise on _all, _best and _finalized for different block header subs

* WIP center subscribing around blocks

* Remove the event filtering/subscribing  stuff

* clippy

* we need tokio, silly clippy

* add extrinsic_index() call

* Update subxt/src/blocks/block_types.rs

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Add dynbamic nested query example and make dynamic::tx a little easier to work with

* calL_value -> inner_tx

* rename example to dynamic_multisig to align with #713 naming

* align dynamic and static multisig examples

* Fix comment typo

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

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

subxt/src/tx/tx_client.rs

@@ -79,7 +79,7 @@ impl<T: Config, C: OfflineClientT<T>> TxClient<T, C> {
     {
         let metadata = self.client.metadata();
         let mut bytes = Vec::new();
-        call.encode_call_data(&metadata, &mut bytes)?;
+        call.encode_call_data_to(&metadata, &mut bytes)?;
         Ok(bytes)
     }
 
@@ -101,7 +101,7 @@ impl<T: Config, C: OfflineClientT<T>> TxClient<T, C> {
             // transaction protocol version (4) (is not signed, so no 1 bit at the front).
             4u8.encode_to(&mut encoded_inner);
             // encode call data after this byte.
-            call.encode_call_data(&self.client.metadata(), &mut encoded_inner)?;
+            call.encode_call_data_to(&self.client.metadata(), &mut encoded_inner)?;
             // now, prefix byte length:
             let len = Compact(
                 u32::try_from(encoded_inner.len())