Investigate if the config used by the API should take the substrate runtime changes

[echevrier]

The runtime changed in substrate:

• https://github.com/paritytech/substrate/commit/c446786a498dee7b413de101efc3c339d3eddf44
• https://github.com/paritytech/substrate/commit/ec3bedd5c8cd0caa77a312b53a3cf3306149276c

[haerdib]

Just noting previously stated observations regarding the Block type: We could remove Header and BlockNumber from our Config. Could look like:

type Block = Block<Header<u32, BlakeTwo256>, OpaqueExtrinsic>; 

(or define some types for better readability outside of Config struct)

Pro:

If one defines the config by self, then one could take the Block type directly from Runtime, and does not need to define Header and Blocknumber.

Config {
..... 

type Block = my_node_runtime::Runtime::Block;
...

}

Disadvantage:

The "inner" types can not be accessed anymore with simple Config::Header but a little more complex with somethign like Conifg::<Block as BlockTrait>::Header.