Optimise updates based on confirmed transactions

[reyraa]

Expected behaviour

We can create a function which iterates over transactions once, and accepts multiple filter functions in pipeline and returns the result once. this saves us from ending up to multiple redundant iterations over all the transactions with every beat of metronome.

Actual behaviour

Presently we filter transactions 3 times for 3 similar goals:

• To get the list recent of transactions with vote type.
• To get the list recent of transactions with register as delegate type.
• To update the number of confirmations

Where all these happen

in store/middlewares/account.js

[slaweet]

It turned out that it would add unnecessary complexity to the code, so we won't do this.