Add a (empty) Report Place, View, and Activity.

Add a (empty) Report Place, View, and Activity.

* src/main/java/org/glom/web/client/place/HasSelectableTablePlace.java:
Rename to:
* src/main/java/org/glom/web/client/place/HasTablePlace.java
* src/main/java/org/glom/web/client/place/ListPlace.java: Move some of
this into a superclass:
* src/main/java/org/glom/web/client/place/HasRecordsPlace.java
and also use it as the base of this new ReportPlace:
* src/main/java/org/glom/web/client/place/ReportPlace.java

* src/main/java/org/glom/web/client/ui/ReportView.java
* src/main/java/org/glom/web/client/ui/ReportViewImpl.java
* src/main/java/org/glom/web/client/activity/ReportActivity.java:
Add these, containing mostly boiler-plate for now.

* src/main/java/org/glom/web/client/OnlineGlomService.java
* src/main/java/org/glom/web/client/OnlineGlomServiceAsync.java
* src/main/java/org/glom/web/server/ConfiguredDocument.java
* src/main/java/org/glom/web/server/OnlineGlomServiceImpl.java:
Add API to get the LayoutGroup for the report.