Extend rule to look into Template Literal and BinaryExpressions

[RatoX]

Fixes https://github.com/JonasBa/eslint-plugin-no-lookahead-lookbehind-regexp/issues/7

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This Pull Request is improving the lint rule to check more edge cases, like:

new RegExp("(?<=)" + "");
new RegExp(`(?<=)`);

However, it still doesn't cover this kind of scenario:

const foo = "(?<=)";
new RegExp(`some content ${foo}`);

That would require a little bit of more code.