Add ten-color accessible color cycle as style sheet

[mpetroff]

PR summary

(Following up from email.)

Adds a style sheet with the ten-color color cycle survey palette from Petroff (2021) [which will be published in a journal eventually]:
https://arxiv.org/abs/2107.02270
https://github.com/mpetroff/accessible-color-cycles

Related to (but does not fix) #9460.

At the moment, this PR contains only the minimal changes. I've only added the ten-color sequence from the paper and only done so as a style sheet.

The paper additionally contains six- and eight-color sequences, which could also be added.

Would it be better to add to _BUILTIN_COLOR_SEQUENCES in lib/matplotlib/colors.py with data in lib/matplotlib/_cm.py instead of as a style sheet?

I'm also open to naming suggestions. The current name is the placeholder I've been using, with ccs standing for "color cycle survey".

PR checklist

• "closes #0000" is in the body of the PR description to link the related issue
• [N/A ] new and changed code is tested
• Plotting related features are demonstrated in an example
• New Features and API Changes are noted with a directive and release note
• Documentation complies with general and docstring guidelines

[tacaswell]

I am very much in favor of taking this, but agree the name needs some workshopping.

We may also want to add these sequence(s) to

matplotlib/lib/matplotlib/colors.py

Lines 119 to 132 in cb8c484

	_BUILTIN_COLOR_SEQUENCES = {
	'tab10': _cm._tab10_data,
	'tab20': _cm._tab20_data,
	'tab20b': _cm._tab20b_data,
	'tab20c': _cm._tab20c_data,
	'Pastel1': _cm._Pastel1_data,
	'Pastel2': _cm._Pastel2_data,
	'Paired': _cm._Paired_data,
	'Accent': _cm._Accent_data,
	'Dark2': _cm._Dark2_data,
	'Set1': _cm._Set1_data,
	'Set2': _cm._Set1_data,
	'Set3': _cm._Set1_data,
	}

[tacaswell]

If it is ready in the next week or so, it can go in 3.9, but I think it is important to get the names and such rather rather than rushing it through.

[kpedro88]

@mpetroff great to see this! As a user, I am in favor of adding the 6- and 8-color cycles.