Enable support for TypeScript in components

Includes: compilation, translations, IDE support (use .tsx not .ts), typings, and other build tools.

TypeScript component have to import PropTypes and React with `import * as React from 'react';`

package.json

@@ -40,7 +40,7 @@
     "rethemendex": "res/css/rethemendex.sh",
     "clean": "rimraf lib",
     "build": "yarn clean && git rev-parse HEAD > git-revision.txt && yarn build:compile && yarn build:types",
-    "build:compile": "yarn reskindex && babel -d lib --verbose --extensions \".ts,.js\" src",
+    "build:compile": "yarn reskindex && babel -d lib --verbose --extensions \".ts,.js,.tsx\" src",
     "build:types": "tsc --emitDeclarationOnly",
     "start": "echo THIS IS FOR LEGACY PURPOSES ONLY. && yarn start:all",
     "start:all": "concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n build,reskindex \"yarn start:build\" \"yarn reskindex:watch\"",
@@ -118,6 +118,7 @@
     "@babel/preset-typescript": "^7.7.4",
     "@babel/register": "^7.7.4",
     "@peculiar/webcrypto": "^1.0.22",
+    "@types/react": "16.9",
     "babel-eslint": "^10.0.3",
     "babel-jest": "^24.9.0",
     "chokidar": "^3.3.1",