add static seo and social_image, description, etc

[btihen]

I like having the image shared when I share a site link (& I like to add to add the opengraph and twitter cards) to my sites. In case you would like this as a standard feature in the starter

[drehimself]

Hmm, getting this error when netlify is trying to build. If it's fixed, will take a look again.

5:45:12 PM: Execute GraphQL (28 queries) - 0.13s
5:45:12 PM: Could not generate HTML for "/tag/design/":
5:45:12 PM: ReferenceError: copyRightNotice is not defined
5:45:12 PM:     at Module.main (src/main.js:32:34)
5:45:12 PM:     at runMain (node_modules/gridsome/app/app.js:55:24)
5:45:12 PM:     at Module.O/VM (node_modules/gridsome/app/entry.server.js:3:0)
5:45:12 PM:     at __webpack_require__ (webpack/bootstrap:25:0)
5:45:12 PM:     at Object.0 (assets/js/app.abc920fb.js:270:18)
5:45:12 PM:     at __webpack_require__ (webpack/bootstrap:25:0)
5:45:12 PM:     at assets/js/app.abc920fb.js:118:18
5:45:12 PM:     at Object.<anonymous> (assets/js/app.abc920fb.js:121:10)
5:45:12 PM:     at o (/opt/build/repo/node_modules/vue-server-renderer/build.prod.js:1:77543)
5:45:12 PM:     at /opt/build/repo/node_modules/vue-server-renderer/build.prod.js:1:78136