2.0 RC 1 - new ConfigurationService (#3810)

* use html5 email validation
* remove static cache seed, for compatibility with non default (file based) caches
* added caching ConfigurationService, removed use of doctrine result cache
* simplify configuration API

config/packages/cache.yaml

@@ -1,11 +1,10 @@
 framework:
     cache:
-        # Unique name of your app: used to compute stable namespaces for cache keys.
-        prefix_seed: "kimai"
-
-        # Redis
         #app: cache.adapter.redis
-        #default_redis_provider: redis://localhost
+        #default_redis_provider: redis://127.0.0.1:6379
+
+        #app: cache.adapter.memcached
+        #default_memcached_provider: 'memcached://localhost'
 
         # APCu (not recommended with heavy random-write workloads as memory fragmentation can cause perf issues)
         #app: cache.adapter.apcu