Export config to make embedded start

This likely requires much more research, and it could be embedded does
not support embedded jars at all, and most have every class in the main
jar.

Signed-off-by: Arjan Tijms <arjan.tijms@omnifish.ee>

appserver/microprofile/config/pom.xml

@@ -78,6 +78,7 @@
                         <!-- A list of packages that are exposed to classes outside the bundle -->
                         <Export-Package>
                             org.glassfish.microprofile.config,
+                            io.helidon.common.config,
                             io.helidon.config.mp,
                             io.helidon.config
                         </Export-Package>