INSTALL.md
* Better organization of CMake options
CMakeLists.txt
* If WITH_XC_NETWORKING is disabled, also disable WITH_XC_UPDATECHECK
* Move KeeShare logic into KeeShare CMakeLists.txt
* Remove WITH_XC_KEESHARE_SECURE build option
* Attempt to find quazip, if found enable WITH_XC_KEESHARE_SECURE and build with secure container support