fix: honor user configured rules

[aladdin-add]

• fix failing tests
• add a test

atm, users cannot disable the rules, as the defaults was always applied.
fixes #670 fixes #613

[aladdin-add]

the build is failing as ?. and ?? was not supported in node v12, will try to make a change later.

[fregante]

Is this still mergeable or necessary? Node 12 is long gone so it shouldn't be blocked anymore.

[sindresorhus]

It may be moot with flat config and I also don't want to take the risk of breakage, since XO is going to change a lot anyway with flat config.

[fregante]

I also don't want to take the risk of breakage

Understandable, but due to both #613 and #598, I'm seeing errors related to Node in a non-Node project, and they require inline exclusions.

One example is:

✖    7:9   The navigator is still an experimental feature The configured version range is >= 20.                                                                          n/no-unsupported-features/node-builtins