composer: Add all details to the composer file

The composer file currently lacks a lot of details, especially the
"name" and "description", but also "require-dev" and "suggest" info.

This commit adds many more details to the composer file and updates
composer.lock for this repository. Technically the project is ready
to be shipped as composer package.

composer.json

@@ -1,12 +1,39 @@
 {
+    "name": "rss-bridge/rss-bridge",
+    "description": "RSS-Bridge is a PHP project capable of generating RSS and Atom feeds for websites that don't have one. It can be used on webservers or as a stand-alone application in CLI mode.",
+    "keywords": [
+        "php",
+        "rss",
+        "bridge",
+        "rss-bridge",
+        "atom",
+        "html",
+        "json",
+        "feed",
+        "cli"
+    ],
+    "homepage": "https://github.com/rss-bridge/rss-bridge/",
+    "license": "UNLICENSE",
+    "support": {
+        "issues": "https://github.com/rss-bridge/rss-bridge/issues/",
+        "wiki": "https://github.com/rss-bridge/rss-bridge/wiki/",
+        "source": "https://github.com/rss-bridge/rss-bridge/",
+        "rss": "https://github.com/RSS-Bridge/rss-bridge/commits/master.atom"
+    },
     "require": {
         "php": ">=5.6",
         "ext-mbstring": "*",
-	"ext-sqlite3": "*",
         "ext-curl": "*",
         "ext-openssl": "*",
         "ext-libxml": "*",
         "ext-simplexml": "*",
         "ext-json": "*"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^6 || ^7"
+    },
+    "suggest": {
+        "ext-memcached": "Allows to use memcached as cache type",
+        "ext-sqlite3": "Allows to use an SQLite database for caching"
     }
 }