configuration: Add the API configuration to the general configuration

This adds the API configuration parameters to the configurtion, so it
will be possible to take them from the configuration file or from the
command line.

The following configuration were defined:
api_port
api_address
api_ui_dir
api_doc_dir

Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>

db/config.hh

@@ -691,6 +691,10 @@ public:
     val(enable_cache, bool, true, Used, "Enable cache") \
     val(enable_commitlog, bool, true, Used, "Enable commitlog") \
     val(volatile_system_keyspace_for_testing, bool, false, Used, "Don't persist system keyspace - testing only!") \
+    val(api_port, uint16_t, 10000, Used, "Http Rest API port") \
+    val(api_address, sstring, "", Used, "Http Rest API address") \
+    val(api_ui_dir, sstring, "swagger-ui/dist/", Used, "The directory location of the API GUI") \
+    val(api_doc_dir, sstring, "api/api-doc/", Used, "The API definition file directory") \
     /* done! */
 
 #define _make_value_member(name, type, deflt, status, desc, ...)    \