Remove deprecations

[davidtheclark]

Addresses #1310.

As you can see from commits, I've tried to:

• Remove emptyLineBefore option for declaration-block-properties-order
• Remove hierarchicalSelectors option from indentation
• Remove stylelint.utils.cssWordIsVariable
• Remove support for non-namespaced plugin rules
• Remove deprecated options from font-family-name-quotes
• Remove deprecated options of function-url-quotes (this plus the above = "contextual quote rule options")

I believe that addresses all the checkboxes in #1310.

Of course the big points to help check here are:

• Documentation is updated accurately and is still helpful.
• No still important tests were removed.

[coveralls]

Coverage increased (+1.2%) to 98.232% when pulling 6dfd78c on remove-deprecations into 7e5951f on v7.

[m-allanson]

Should this test be replaced with a test to check for a config error? Or should the file plugin-slashless-warn-about-foo.js be removed?

[davidtheclark]

Yeah, these are good ideas. Thanks for looking closely!

[davidtheclark]

In latest commit added a test, as you can see below.

[coveralls]

Coverage increased (+1.2%) to 98.255% when pulling 80c9bf5 on remove-deprecations into 7e5951f on v7.

[jeddy3]

Oh wow. Great to see this. I'm confident we're on a more sustainable trajectory with these removals.

Thanks also for bringing the contextual quote rules inline with the expected and rejected convention.

Feel free to merge after a rebase.

[ntwb]

Nice, and a nice bump in coverage also 👍

Coverage increased (+1.2%) to 98.255%