Validate filters for getter methods in Account and Transaction entities

[lsilvs]

Expected behavior

I expect the storage entities Account and Transaction to validate the passed filters and throw and error if a filter is not valid.
Also, unit tests should be added to cover this scenario.

Actual behavior

Currently it doesn't and the database query crashes with an unclear message

Steps to reproduce

Run storage.entities.Transaction.get({ invalid_filter: true })

Which version(s) does this affect? (Environment, OS, etc...)

1.5