350389: improve Scout RT testing support 

Change-Id: I513bd9da00f3822ecac47d9a423b56f730e15e63
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=350389
Signed-off-by: Matthias Fischer <mfi@bsiag.com>
Reviewed-on: https://git.eclipse.org/r/35232
Tested-by: Hudson CI
Reviewed-by: Judith Gull <jgu@bsiag.com>
442649: Scout Admin Pages / Sessions: Wrong session timestamps 

Read Session timestamps from HttpSession, gracefully handle null values.
Some refactoring of SessionsView class.

Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=442649

Change-Id: I2bf7d1863c3d51d58c14d40672bdde1b2feff941
Signed-off-by: Lukas Huser <lhu@bsiag.com>
Reviewed-on: https://git.eclipse.org/r/35254
Tested-by: Hudson CI
Reviewed-by: Judith Gull <jgu@bsiag.com>