Create multiple transaction classes for each type

[marioevz]

          We could create separate class types for each Transaction at some point in the future, i.e TransactionType0, ..., TransactionType3 that are members of Transaction to avoid duplication

This could be useful when writing tests later down the line to improve readability, maintenance, etc

Originally posted by @spencer-tb in #167 (comment)

[winsvega]

I am up for this. Currently the init data must be prepared ahead.

txdata = {...}
tx = Transaction(**txdata)    // transaction derrives it's type from the given data

I used to have the approach like this:

tx = TransactionA()  // default  values
tx.gas_limit = 100_000   // override default values.  

but also having different transaction type classes makes it better IMHO.
so you don't store all the logic at one place. but extend it by overriding the base class