New: Unsafe integer rule

[jdoubleu]

Prerequisites checklist

• I have read the contributing guidelines.
• The team has reached consensus on the changes proposed in this pull request. If not, I understand that the evaluation process will begin with this pull request and won't be merged until the team has reached consensus.

What is the purpose of this pull request? (put an "X" next to an item)

• Documentation update
• Bug fix (template)
• New rule (template)
• Changes an existing rule (template)
• Add autofixing to a rule
• Add a CLI option
• Add something to the core
• Other, please explain:

New Rule

Please describe what the rule should do:
Due to IEEE-754 double precision, integers with a value higher or equal to 2^53 cannot properly be represented in JavaScript and are therefore considered unsafe.

What category of rule is this? (place an "X" next to just one item)

• Warns about a potential error (problem)
• Suggests an alternate way of doing something (suggestion)
• Enforces code style (layout)
• Other (please specify:)

Provide 2-3 code examples that this rule will warn about:

/*eslint no-unsafe-integer: "error"*/

var num1 = 9223372036854775807; // INT64_MAX_NUMBER
var num2 = 0x7FFFFFFFFFFFFFFF; // INT64_MAX_NUMBER in hex
parseInt("9007199254740992");

Why should this rule be included in ESLint (instead of a plugin)?
It is a very minimal and simple rule which does not produce much overhead. Although I'd guess this rule does not apply to all code bases, when detected it could save a few minutes and quickly resolve confusion about JavaScript's Number object.

What changes did you make? (Give an overview)

1. Add new rule definition in lib/rules/,
2. add tests for that rule,
3. add documentation for the rule.

Is there anything you'd like reviewers to focus on?

Documentation: Rule Description.

[jsf-clabot]

All committers have signed the CLA.

[jdoubleu]

This rule is missing checking for constant calculations (e.g. 2 ** 80.

However I'll wait for the discussion at #11279 before updating this PR.

[jdoubleu]

Closed in favor of #11279