feat: OHIF-117 ohif extension default (#1712)

* initial structure for extension default

* webpack config

* split default modules into separated files

* bump versions

* update index

* update index

* fix

* Co-authored-by: Danny Brown <danny.ri.brown@gmail.com>

extensions/default/package.json

@@ -0,0 +1,39 @@
+{
+  "name": "@ohif/extension-default",
+  "version": "1.0.1",
+  "description": "Common/default features and functionality for basic image viewing",
+  "author": "OHIF Core Team",
+  "license": "MIT",
+  "repository": "OHIF/Viewers",
+  "main": "dist/index.umd.js",
+  "module": "src/index.js",
+  "publishConfig": {
+    "access": "public"
+  },
+  "engines": {
+    "node": ">=10",
+    "npm": ">=6",
+    "yarn": ">=1.19.1"
+  },
+  "files": [
+    "dist",
+    "README.md"
+  ],
+  "scripts": {
+    "dev": "cross-env NODE_ENV=development webpack --config .webpack/webpack.dev.js --watch --debug --output-pathinfo",
+    "dev:dicom-pdf": "yarn run dev",
+    "build": "cross-env NODE_ENV=production webpack --config .webpack/webpack.prod.js",
+    "build:package": "yarn run build",
+    "start": "yarn run dev"
+  },
+  "peerDependencies": {
+    "@ohif/core": "^0.50.0",
+    "prop-types": "^15.6.2",
+    "react": "^16.13.1",
+    "react-dom": "^16.13.1",
+    "webpack": "^4.0.0"
+  },
+  "dependencies": {
+    "@babel/runtime": "7.7.6"
+  }
+}