LT-14165 Remove sample projects from installer

 * Also cease creation of default parent folder of "Projects" to stop
   that folder being created even when user puts projects elsewhere
 * Fix glitch in build report that complains about Utilities.dll
 * Add (as experiment) config settings to cache & reuse .cab files.

Change-Id: Ie4f853b899621f43dab0b481949d8f1899ec42d7