[SysApps] Remove usage of XWalkRuntimeFeatures

This was the only dependency that sysapps/ had from runtime/. We keep
the usage of the XWalkRuntimeFeatures (which parses command line) in
runtime/ and add specific functions to disable each API.

This patch is a first step to clean up the handling of extension
creation in the Android and Tizen variants. At the moment, creation of
the extensions in those ports is bypassing the SysAppsManager.