utils: invoke: Raise exceptions using SRFI-34 and SRFI-35.

utils: invoke: Raise exceptions using SRFI-34 and SRFI-35.

* guix/build/utils.scm (&invoke-error): New condition type.
(invoke-error?, invoke-error-program, invoke-error-arguments)
(invoke-error-exit-status, invoke-error-term-signal)
(invoke-error-stop-signal): New exported procedures.
(invoke): Raise exceptions using SRFI-34 and SRFI-35.
* guix/ui.scm (call-with-error-handling): Add a guard clause
for &invoke-error conditions.