Add switches to barclamp_install to skip certain installation steps

This adds the following new commandline switches. Both are required when using barclamp_install for within the package building process (e.g. inside the %install section of a spec file when building RPMs):
--no-migrations: To not run execute the database migrations
--no-framework-install: To skip the basic step of laying out the base files in the correct subdirectory (use this on the installed system, when calling barclamp_install for a barclamp that was installed from a packages.