* ttcn3-{ggsn,pgw}-test: Avoid open5gs itself logging to a file
* ttcn3-pgw-test: Log open5gs-nrfd stdout/stderr
* ttcn3-pgw-tests: use same bootstrap for upfd as in ttcn-ggsn-tests-ogs
* ttcn3-{pgw,ggsn}-tests: Add comment with procedure to get open5gs-smfd bt automatically
* ttcn3-pgw-test: Use process name in log file
* ttcn3-pgw-test: Log stdout to find crashes
* ttcn3-ggsn-ogs: Rename config files