Add Blaze User Setting for FastBuild Java Binary Path

[dtaveras]

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• I have filed an issue about this change and discussed potential changes with the maintainers.
• I have received the approval from the maintainers to make this change.
• This is not a stylistic, refactoring, or cleanup change.

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Discussion thread for this change

Issue number: https://github.com/bazelbuild/intellij/issues/6432

Description of this change

Add a user setting where the fastbuild binary path can be specified. I couldn't think of a way to programmatically derive it.

[mai93]

Thanks @dtaveras! added a small comment otherwise LGTM