status: Add 'with-status-verbosity'.

status: Add 'with-status-verbosity'.

* guix/status.scm (logger-for-level, call-with-status-verbosity): New
procedures.
(with-status-verbosity): New macro.
* guix/scripts/environment.scm (guix-environment): Use
'with-status-verbosity' instead of 'with-status-report'.
* guix/scripts/pack.scm (guix-pack): Likewise.
* guix/scripts/package.scm (guix-package): Likewise.
* guix/scripts/pull.scm (guix-pull): Likewise.
* guix/scripts/system.scm (guix-system): Likewise.
* build-aux/run-system-tests.scm (run-system-tests): Likewise.