Add back exports to the org.eclipse.swt host (#1032)

Some projects, like BND tools, will avoid using require-bundle
at great lengths. This becomes problematic when the APIs they
want to use do not version there `Export-Package` properly.

Many Eclipse projects, including SWT, do not version their API
packages.  They only version their individual bundles with respect
to semantic versioning.

For BND they resorted to using `Import-Package` with the
`bundle-version` and `bundle-symbolic-name` of the host. This
"worked" because the SWT API packages were defined in the
`Export-Package` header of the host bundle. But now with
PR #1008 this changed and the host bundle no longer defines
the exported packages. The end result is BND tools is now
broken and has many unresolvable bundles.

Until this is sorted out, this PR simply adds back the
`Export-Package` header of the SWT host. The longer term
solution should be to properly version SWT API packages
so that consumers of the API can properly use `Import-Package`
to depend on the API.

bundles/org.eclipse.swt/META-INF/MANIFEST.MF

@@ -6,6 +6,22 @@ Bundle-Version: 3.125.0.qualifier
 Bundle-ManifestVersion: 2
 Bundle-Localization: plugin
 DynamicImport-Package: org.eclipse.swt.accessibility2
+Export-Package: 
+ org.eclipse.swt,
+ org.eclipse.swt.accessibility,
+ org.eclipse.swt.awt,
+ org.eclipse.swt.browser,
+ org.eclipse.swt.custom,
+ org.eclipse.swt.dnd,
+ org.eclipse.swt.events,
+ org.eclipse.swt.graphics,
+ org.eclipse.swt.internal,
+ org.eclipse.swt.internal.image;x-internal:=true,
+ org.eclipse.swt.layout,
+ org.eclipse.swt.opengl,
+ org.eclipse.swt.printing,
+ org.eclipse.swt.program,
+ org.eclipse.swt.widgets
 Eclipse-ExtensibleAPI: true
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Automatic-Module-Name: org.eclipse.swt