Use optional resolution of sun.net.dns (#13303)

Motivation:

To be able to use our DNS resolver with OSGI we should use an optional resolution of sun.net.dns

Modifications:

Add config to pom.xml

Result:

Fixes #13297

pom.xml

@@ -1556,7 +1556,7 @@
               <instructions>
                 <Export-Package>${project.groupId}.*</Export-Package>
                 <!-- enforce JVM vendor package as optional -->
-                <Import-Package>sun.misc.*;resolution:=optional,sun.nio.ch;resolution:=optional,sun.security.*;resolution:=optional,org.eclipse.jetty.npn;version="[1,2)";resolution:=optional,org.eclipse.jetty.alpn;version="[1,2)";resolution:=optional,*</Import-Package>
+                <Import-Package>sun.net.dns.*;resolution:=optional,sun.misc.*;resolution:=optional,sun.nio.ch;resolution:=optional,sun.security.*;resolution:=optional,org.eclipse.jetty.npn;version="[1,2)";resolution:=optional,org.eclipse.jetty.alpn;version="[1,2)";resolution:=optional,*</Import-Package>
                 <!-- override "internal" private package convention -->
                 <Private-Package>!*</Private-Package>
               </instructions>