Eliminate Output macro in favor of simple Env functions (#7223)

Eliminate Output macro in favor of simple Env functions (#7223)

This PR eliminates the Output macro together with the associated output stream (stored in a static variable). It is replaces by a set of simple utility functions of the Env class, and we instead use the output stream from options.base.out.
To achieve this, a couple of quantifier classes are now derived from EnvObj.