Add support for new headless quick fixes from upstream

[gayanper]

Add new quick fixes namely

• ChangeLambdaBodyToBlock
• ChangeLambdaBodyToExpression
• ConvertLambdaToMethodReference
• AddInferredLambdaParameterTypes
• AddVarLambdaParameterTypes
• RemoveVarOrInferredLambdaParameterTypes
• InvertEqualsExpression

[gayanper]

@jjohnstn @rgrunber Please review

[robstryker]

Code looks neat and orderly. I like the addition of tests. The only complaint I have is more of a stylistic complaint, in that I've not seen the jdt-ls project use the 'var' type at all. In fact, the only file I see using it is ProgressReporterManager.

I'm not saying its wrong or needs to be changed. Just pointing out that it doesn't seem to be part of our normal conventions. Still, I'll let @rgrunber decide whether we have "rigorous coding standards" or if we're more of a free-wheeling repo ;)

[rgrunber]

There's definitely a push at Eclipse to use newer language features (pretty much anything up to Java 17 is fair game). var is a bit interesting in that it definitely seems to remove information that would have been very clear without even loading the codebase into an IDE, which has implications for doing shallow reviews / instant feedback.

On the other hand, the var usages here are either on the same line, or within a few lines of its initialization, or matching the type of the member that's called statically, so it remains readable, and not really an issue.