Java function rework

[Efnilite]

Problem

In preparation for named function arguments, which allows changing the order of appearance of function arguments, a replacement has to be created for JavaFunctions. JavaFunctions use indices to get function arguments, which is incompatible with the planned design for functions.

Other than that, registering functions is just really ugly. This PR improves that.

Old

New

This is a part of the larger function rework.

Solution

A DefaultFunction has several advantages over a JavaFunction.

• DefaultFunction has a much more modern function builder, resulting in nicer looking code.
• DefaultFunction utilizes Java types to specify exactly what arguments to expect. When defining a parameter, instead of having to use a ClassInfo and then specifying that it accepts multiple inputs separately, you can now simply write String[].class.
• DefaultFunction removes some confusing behaviour from JavaFunctions. For example, in the location function, the amount of worlds would sometimes be more than one. This is bad design, as the world parameter is defined as being single. DefaultFunction now correctly selects a single world.
• DefaultFunction now allows you to get arguments by their name, instead of their index, which results in clearer code.
• DefaultFunction has no children, reducing the inheritance as seen in (Simple)JavaFunction.
• DefaultFunction supports String arrays in its since method.

Testing Completed

• Added JUnit tests
• Converted some high usage JavaFunctions to DefaultFunctions, and made sure that their tests run

Supporting Information

• Deprecates JavaFunction, SimpleJavaFunction.
• Updates documentation classes to use Function instead of JavaFunction

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Completes: none
Related: #7590 (since array support)

[UnderscoreTud]

This is a huge improvement over the old functions, good job!!

[Absolutionism]

Looks good, I like the change.

[APickledWalrus]

Just marking that I need to review this again

[APickledWalrus]

looks pretty good. almost ready