I piggyback on ssl-cert package that's got ssl-cert group and the
directory /etc/ssl/private, the group can read files from (but not list
files there). Thus, by adding a user to ssl-cert group, they can read
both ssl-cert certificates and the KasmVNC certificate.o
Note: currently, KasmVNC only supports one file that must contain both
private and public keys. For this reason, I didn't use the snakeoil
certificate from ssl-cert, as it's split into two files.
