sysutils/pot: Update to 0.15.4
Includes adding a new group "pot" which is used to grant
unprivileged users access to read-only pot commands.
Depend on security/signify for pot image signatures.
While there, add a stub man page so users entering `man pot` see
something slightly useful, readd pkg-message.in to package.
Add a longer pkg-descr to make portlint happy.
Approved by: pizzamig (maintainer)
sysuilts/pot: Update to 0.9.0
Many changes, from 0.6.1 to 0.9.0
A lot of work to make pot more friendly and to be used with nomad.
Sponsored by: trivago N.V.