Add plugins UI improvements

[oli-rose28]

What

Improve the plugins UI

Why

We've prototyped improvements to the plugins UI after the latest round of UR

Who needs to work on this

• Developers

Who needs to review this

Done when

• The improvements to plugins v2 have been built: https://www.figma.com/file/sWnqT4u4uup91TuTe9T3tp/GOV.UK-Prototype-Kit?type=design&node-id=321-2&mode=design&t=C8QhLHcbaRWDLqgA-0

• Find plugins: improved side nav, including content changes and 'update available' label

• Find plugins: total number of plugins 'X plugins found'

• Find plugins: remove 'From' before the plugin author

• Find plugins: order plugins list alphabetically

• Find plugins: add pagination

• Installed plugins: mostly the same as 'find plugins'

• Install plugin: Include 'about this plugin' section and link to ‘how to use this plugin’

• Install plugin: add 'what's included in this plugin' section

• Install plugin: add release notes link

• Install plugin: add version history link

• Install plugin: add 'report plugin' link (goes to our contact page)

• Installed plugin: mostly the same as 'install plugin'