Improve plugin NPM pages

[mikenikles]

Our first Webstone Plugin is available at https://www.npmjs.com/package/webstone-plugin-request-logger-web.

We need to update our plugins so the NPM pages include the following:

• Repository
• Homepage

We also need a section right above "Learn more about Webstone Plugins" called "Report bugs, request features" (or similar). Provide two links in that paragraph:

• Report bug
• Request feature

Each links to its own GitHub issues template, pre-populated with a label for the correct NPM package.

Open questions

• How does the "Report bugs, request features" section work for plugins written by the community? I'm thinking a TODO in the README.md with instructions on how to create issue templates so plugin authors can easily set that up.