Docs: Add Coiled to list of paid support organizations

[koverholt]

Coiled offers paid support and training for Dask. This PR:

• Add Coiled to list of paid support organizations in docs
• Add note that the list of paid support organizations is listed in alphabetical order

[jrbourbeau]

This seems okay to me, but since I work for Coiled I'll leave it to another maintainer employed by someone else (like @jsignell or @martindurant) to handle this PR.

Also, +1 for making this list alphabetically ordered as to not indirectly communicate a relative priority between the listed organizations

[jrbourbeau]

Also, @jsignell you previously commented that Saturn shouldn't go in this "Paid Support" section (xref #6795 (comment)). Just wanted to check in to see if that's still the case, or if we should also add Saturn here.

[jsignell]

Yeah this seems reasonable to me. Thanks for the ping and 👋 @koverholt

[jsignell]

I'll wait until the end of the day to merge to see if @martindurant has any comments.

[martindurant]

Certainly fine with me. Alphabetical listing general works to Anaconda's advantage, but doesn't matter while the list is short anyway. Should that change, we may want to make it randomised.

[koverholt]

Thanks @jsignell 🤘 and @martindurant for your input/help here!