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.
Fix a case where `ripple::Expected` returned a json array, not a value.
The problem was that `Expected` invoked the wrong constructor for the
expected type, which resulted in a constructor that took multiple
arguments being interpreted as an array.
A proposed fix was provided by @godexsoft, which involved a minor
adjustment to three constructors that replaces the use of curly braces
with parentheses. This makes `Expected` usable for
[Clio](https://github.com/XRPLF/clio).
A unit test is also included to ensure that the issue doesn't occur
again in the future.
