Refactored code to protocol oriented

[acoroian]

Hello,

I have refactored the code to protocol oriented.
This cleaned up some single responsibility issues.

EthTypeEncoder - can be broken up to separate files for each extension
Everything conforms to EthEncodable. The benefits are:

• no more need to throw error if type is not encodable.
• issues are seen at compile time
• cleaner usage of encoder functions
• people can extend their type to make it encodable and usable by library.

Code has not been tested but should work the same (unless i missed someting).
TODO: Write tests to confirm everything is working