Add Rubocop rule to catch arrays of size > 300. Also fix a bunch of .rubocop_todo.yml

[jneen]

Adds a custom cop to deal with huge array literals not in lazily-loaded files. I will be going through the todo file and fixing these in the next few weeks.

Also disables the following Rubocop rules:

• Lint/OutOfRangeRegexpRef is just broken as far as I can tell, it is catching perfectly valid uses of these refs.
• Lint/MissingSuper is just not helpful most of the time in this project
• Lint/ToEnumArguments is not able to tell when arguments are deprecated, and is therefore not actionable and just noise
• Lint/NextedPercentLiteral is full of false-positives on account of the strange string literals we have to deal with in this project
• Lint/DuplicateBranch after fixing a number of these (though I included the fixes) I concluded that most instances caught were not actually problems.
• Naming/MethodParameterName encourages huge variable names when small ones will do
• Naming/HeredocDelimiterNaming is useless and annoying
• Naming/VariableNumber is very opinionated on a very strange opinion