[New] no-namespace: Add ignore option

[aberezkin]

Closes #1916
Closes #1903

Hi, we want to use the rule no-namespace in our project but we have a i18n codegen tool that forces us to use wildcard imports for certain files that follow some pattern (\S+\.i18n, to be precise). Also I've seen that there's people with similar issue.

I thought that we can implement something similar to argsIgnorePattern/varsIgnorePattern in core eslint rules.

I made a test for that case and updated the docs as well. Please let me know if there's something else I should do to get this merged.

[coveralls]

Coverage increased (+0.9%) to 82.635% when pulling 0c4e324 on aberezkin:ignore-from-pattern-for-no-namespace into 7aea664 on benmosher:master.

[aberezkin]

Hi @ljharb! Can you look at this PR? It's quite similar to #1916. But adds a little more versatile option.

[gairon]

Hi @aberezkin, any updates on that ? Have the same problem with this rule.

[aberezkin]

Hi @gairon. I would be happy to provide some update but I can't merge it myself since I'm not a maintainer 😄

[gairon]

Who else can help with verifying and pushing a really cool feature?
@ljharb @benmosher ?

[aberezkin]

@ljharb Fixed! :)

[gairon]

Hi @aberezkin,
thanks for the new option.
Found a typo in docs:
/* eslint import/no-namespace: ["error", {ignore: ['*.ext']] */
there missed } before last ].

[ljharb]

@gairon thanks, fixed in 4f0f560