Add Readme.md file

Thanks for getting this started. Noticing that these links are off.

+## Configuration
+
+1. Download [Entity Browser](https://www.drupal.org/project/content_browser) from Drupal.org
+2. Download [Entity Embed](https://www.drupal.org/project/content_browser) from Drupal.org

Per issues 2971165 → how masonry is added is changing. Also the version you have added is older.

https://www.drupal.org/files/issues/2019-05-14/2971165-3-composer-install-masonry.patch+{
+  "name": "drupal/content_browser",
+  "type": "drupal-module",
+  "homepage": "http://drupal.org/project/content_browser",
+  "repositories": {
+    "masonry": {
+      "type": "package",
+      "package": {
+        "name": "desandro/masonry",
+        "version": "4.2.2",
+        "type": "drupal-library",
+        "dist": {
+          "url": "https://github.com/desandro/masonry/archive/v4.2.2.zip",
+          "type": "zip"
+        }
+      }
+    }
+  },
+  "require": {
+    "desandro/masonry": "4.2.2"
+  }
+}

Please review.

Hi nitin_lama

I reviewed your changes and it changed the correct link for the "Requirements" modules and it follows the README.md template.

Thank you