js: port MAX_SAFE_INTEGER + friends

[timotheecour]

/cc @juancarlospaco @xflywind

# https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER
Number.EPSILON
Number.MAX_SAFE_INTEGER
Number.MAX_VALUE
Number.MIN_SAFE_INTEGER
Number.MIN_VALUE
Number.NaN
Number.NEGATIVE_INFINITY
Number.POSITIVE_INFINITY

# https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger
Number.isSafeInteger

and other procs/constants related to Number

std/jsffi comes to mind but IMO this module is bloated and has a bad designed (everything is a JsObect makes no sense to me, making it hard to use)

so the best would be a new module, maybe std/jsnumbers ? or some broader scope?

example use cases

• refactor hash in JS backend nim-lang/Nim#16863 (comment)

[juancarlospaco]

jsnumbers