This is a major refactor of LedgerEntry.cpp. It adds a number of helper functions to make the code easier to maintain.
It also splits up the ledger and ledger_entry tests into different files, and cleans up the ledger_entry tests to make them easier to write and maintain.
This refactor also caught a few bugs in some of the other RPC processing, so those are fixed along the way.
The codebase is filled with includes that are unused, and which thus can be removed. At the same time, the files often do not include all headers that contain the definitions used in those files. This change uses clang-format and clang-tidy to clean up the includes, with minor manual intervention to ensure the code compiles on all platforms.
