[FEATURE] Implement BigInt

[naijun0403]

~~Can you implement here what was implemented in the original Rhino now?

for example: BigInt, globalThis, Promise~~

Edit: BigInt must be supported.

[mattco98]

Can you be more specific? I might add something if someone requested it, but just saying "add everything that isn't implemented" isn't too helpful. Is there something in particular you need?

[naijun0403]

Actually, there is no major inconvenience, but BigInt support seems to be particularly important.

For example, it would be nice to include grammar like 1n!

I can do it directly with java.lang.Long or java.math.BigInteager, but I think need to use BigInt natively to handle large numbers.

I will change the issue name accordingly.