docs(www): link to plugin README templates from plugins guide

[k-conway]

update creating-plugins guide to include plugin template link

Description

update creating-plugins guide to include plugin template link

Related Issues

Fixes issue #14774

[gillkyle]

Thanks for working on this @k-conway!

I moved the note into the submitting a plugin page because I think this will direct users there when they're closer to finishing up their plugin

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