[EPIC] Help users create and use plugins

[joelanman]

What

Plugins let users share common code such as components, templates and filters. It's a powerful feature but we need to document it and make sure users can easily create, share and use them.

Why

We need to make sure people can easily create plugins, if not the feature won't get used or used as much as it could be.

Done when

Better interface

• Plugins - redesign the user interface  #740
• Is it obvious enough when users should update core plugins #2051
• Users have to update the kit to update the Available Plugins list #1985
• Allow plugin developers to specify that their plugin is dependent on other plugins #2125
• When updating a plugin relevant dependencies should be installed (the same UX as installing a plugin) #2242
• Revisit how unbranded/opting out of GOV.UK Frontend works #1705
• Add more plugins to the known/available plugins list #1866

Non GOV.UK prototypes

• Users are able to create prototypes with plugins other than GOV.UK Frontend #2166
• Investigate the NHS fork of the Kit #2167

User research

• Plugins - Recruit for user testing UI and UX changes #2156
• Plugins - user research with plugin authors #751
• Plugins - user research for non-GOV.UK themed prototypes #2176

Assurance

• Decide if plugin assurance/accreditation process is needed #2155
• Draft plugin assurance process #2154

Plugin authors

• Plugins - Add documentation for plugins govuk-prototype-kit-docs#188
• Tools to help plug-in authors test their plug-ins #1635
• Allow plugins to use config in config.js #2148 (low priority, will include if there's time)

[BenSurgisonGDS]

I think it would be easy to create a skeleton plugin from within the manage-prototype pages that could then be treated as a separate project. We could even initialize git for it.