AnalysisContainer no longer held in memory by PluginData objects.

Since PluginData objects are more persistent than AnalysisContainer,
objects related to the each analysis can not be freed until the next
analysis has been performed, because a reference was held in each
PluginData object.

Change: set the reference to point to null in a finally block after
getServerData call. AnalysisContainer can now be freed by GC at any time

Affected issues: #685

Plan/src/main/java/com/djrapitops/plan/utilities/html/structure/AnalysisPluginsTabContentCreator.java

@@ -118,6 +118,7 @@ public class AnalysisPluginsTabContentCreator {
                 Log.toLog(AnalysisPluginsTabContentCreator.class, e);
             } finally {
                 Benchmark.stop("Analysis", "Analysis: Source " + source.getSourcePlugin());
+                source.setAnalysisData(null);
             }
         });
         return containers;