[Enhancement] Required changes to generate a Tax-Report

[marvin-we]

Hello together,

first things first: Thank you all for doing this! I stopped participating in steem and the development of SteemJ in 2018 as generating a tax report for myself was a very tough fight. While fighting my way through the things, I've done some notes and created #2867 based on that ( #3116 seems to be connected too).

The main things are, that:

• all operations that change one of the balances (Savings, HP, HBD, ...) needs to be returned when Operations are queried.
• the factor between vests and hive (m_vests_per_hive?) needs to be accessible for each operation / block (I don't know exactly when it changes).

Would be very nice if this could be improved.

Thank you once again and best regards!