frole: Adjust behaviour for templates; allow specifying totem

The syntax to give 'foo' the additional 'bar' template is now
!frole foo +bar
or, in the case of templates like gunner that can take an argument,
!frole foo +gunner = 9001
Removing a template uses - instead:
!frole foo -bar

The new "role = arg" syntax also applies for shamans and crazed shamans:
!frole foo shaman = impatience
A random totem is selected as usual, rather than the bot crashing, if no
argument is given.
myrole: Only tell shamans their totem at night