User not in dialout group can't access tty*

[Stefal]

In these cases, str2str can't acces the gnss receiver

We should check the group ownership and add dialout if needed.

[Stefal]

The way we check dialout group membership doesn't work. The test is a success in all cases, but:

stephane@rtkbase-test:~$ sudo groups stephane
stephane : stephane dialout cdrom floppy sudo audio dip video plugdev netdev bluetooth
stephane@rtkbase-test:~$ groups stephane
stephane : stephane dialout cdrom floppy sudo audio dip video plugdev netdev bluetooth
stephane@rtkbase-test:~$ groups
stephane cdrom floppy sudo audio dip video plugdev netdev bluetooth

See the last groups command. ~~And in this case (user not a dialout member before the RTKBase installation), str2str_tcp can't acces /dev/tty* and the script doesn't warn the end user that he must reboot.~~

My mistake, the gnss receiver was not connected during the installation, so the tty was a wrong one.