add missing SVGs

This commit adds missing SVGs to `org.eclipse.pde` bundles.

Example content in `exsd` files is also changed to svg even though this
has no direct impact on any icons.

One reference of the icon `ant.png` in the bundle  `org.eclipse.ant.ui`
is changed to SVG as this bundle is already updated for using SVGs.

Author: Michael5601

org.eclipse.pde.doc.user/forceQualifierUpdate.txt

@@ -1,2 +1,3 @@
 https://github.com/eclipse-pde/eclipse.pde/pull/1665
 https://github.com/eclipse-pde/eclipse.pde/pull/1724
+https://github.com/eclipse-pde/eclipse.pde/pull/1788

ui/org.eclipse.pde.spy.core/fragment.e4xmi

@@ -25,7 +25,7 @@
     </elements>
   </fragments>
   <fragments xsi:type="fragment:StringModelFragment" xmi:id="_D-9ugOmnEei5O53ZMcQRyw" featurename="snippets" parentElementId="xpath:/">
-    <elements xsi:type="basic:TrimmedWindow" xmi:id="_I_PxgOmnEei5O53ZMcQRyw" elementId="org.eclipse.pde.spy.core.window" selectedElement="_UUrRUOmqEei5O53ZMcQRyw" label="%E4-Spies-window" iconURI="platform:/plugin/org.eclipse.pde.spy.core/icons/spyicon.png" width="600" height="1000">
+    <elements xsi:type="basic:TrimmedWindow" xmi:id="_I_PxgOmnEei5O53ZMcQRyw" elementId="org.eclipse.pde.spy.core.window" selectedElement="_UUrRUOmqEei5O53ZMcQRyw" label="%E4-Spies-window" iconURI="platform:/plugin/org.eclipse.pde.spy.core/icons/spyicon.svg" width="600" height="1000">
       <persistedState key="persistState" value="false"/>
       <children xsi:type="basic:PartStack" xmi:id="_UUrRUOmqEei5O53ZMcQRyw" elementId="org.eclipse.pde.spy.core.partStack"/>
       <trimBars xmi:id="_MYxKsOmqEei5O53ZMcQRyw" elementId="org.eclipse.pde.spy.core.trimbar">