Remove all example bundles and products and references to them

- The products have not been built for a long time and have
broken/unmaintained dependencies.
- The examples are used only in the products so are pointless after the
removal of the products.

bundles/org.eclipse.equinox.p2.core/META-INF/MANIFEST.MF

@@ -9,7 +9,6 @@ Bundle-Localization: plugin
 Export-Package: org.eclipse.equinox.internal.p2.core;x-friends:="org.eclipse.equinox.p2.publisher,org.eclipse.equinox.p2.repository",
  org.eclipse.equinox.internal.p2.core.helpers;
   x-friends:="org.eclipse.equinox.frameworkadmin.test,
-   org.eclipse.equinox.p2.examples.rcp.prestartupdate,
    org.eclipse.equinox.p2.artifact.optimizers,
    org.eclipse.equinox.p2.artifact.processors,
    org.eclipse.equinox.p2.artifact.repository,

bundles/org.eclipse.equinox.p2.tests.ui/All p2 UI tests.launch

@@ -379,12 +379,6 @@
         <setEntry value="org.eclipse.equinox.p2.discovery.compatibility@default:default"/>
         <setEntry value="org.eclipse.equinox.p2.discovery@default:default"/>
         <setEntry value="org.eclipse.equinox.p2.engine@default:default"/>
-        <setEntry value="org.eclipse.equinox.p2.examples.rcp.cloud@default:default"/>
-        <setEntry value="org.eclipse.equinox.p2.examples.rcp.discovery@default:default"/>
-        <setEntry value="org.eclipse.equinox.p2.examples.rcp.prestartupdate@default:default"/>
-        <setEntry value="org.eclipse.equinox.p2.examples.rcp.sdkbundlevisibility@default:default"/>
-        <setEntry value="org.eclipse.equinox.p2.examples.rcp.sdknoautoupdates@default:default"/>
-        <setEntry value="org.eclipse.equinox.p2.examples.rcp.sdkui@default:default"/>
         <setEntry value="org.eclipse.equinox.p2.extensionlocation@default:default"/>
         <setEntry value="org.eclipse.equinox.p2.garbagecollector@default:default"/>
         <setEntry value="org.eclipse.equinox.p2.installer@default:default"/>

bundles/org.eclipse.equinox.p2.ui/META-INF/MANIFEST.MF

@@ -19,7 +19,6 @@ Export-Package: org.eclipse.equinox.internal.p2.ui;
  org.eclipse.equinox.internal.p2.ui.dialogs;
   x-friends:="org.eclipse.equinox.p2.ui.admin,
    org.eclipse.equinox.p2.ui.sdk.scheduler,
-   org.eclipse.equinox.p2.examples.rcp.discovery,
    org.eclipse.equinox.p2.ui.sdk,
    org.eclipse.pde.ui,
    org.eclipse.equinox.p2.ui.importexport",