Convert most of tag page to react

.babelrc.js

.editorconfig

.eslintrc.js

.gitignore

.prettierrc

index.js

package-lock.json

package.json

sitegin/config.js

sitegin/index.js

sitegin/nunjucks.js

sitegin/templates.js

sitegin/theme.js

static/theme/favicons/android-chrome-144x144.png

static/theme/favicons/android-chrome-192x192.png

static/theme/favicons/android-chrome-36x36.png

static/theme/favicons/android-chrome-48x48.png

static/theme/favicons/android-chrome-72x72.png

static/theme/favicons/android-chrome-96x96.png

static/theme/favicons/apple-touch-icon-114x114.png