feat: support serialization of array, span and unordered_map (#342)

* feat: support serialization of array, span and unordered_map

* fix some spelling mistakes

* docs: update table of valid c++ types

---------

Co-authored-by: Marcel Hellwig <github@cookiesoft.de>

tests/integrationtests/org.sdbuscpp.integrationtests.xml

@@ -45,7 +45,7 @@
             <arg type="(ix)" direction="in" />
             <arg type="i" direction="out" />
         </method>
-        <method name="sumVectorItems">
+        <method name="sumArrayItems">
             <arg type="aq" direction="in" />
             <arg type="at" direction="in" />
             <arg type="u" direction="out" />