managesieve: Emit command events.

src/managesieve/cmd-deletescript.c

src/managesieve/cmd-getscript.c

src/managesieve/cmd-havespace.c

src/managesieve/cmd-listscripts.c

src/managesieve/cmd-putscript.c

src/managesieve/cmd-renamescript.c

src/managesieve/cmd-setactive.c

src/managesieve/managesieve-client.c

src/managesieve/managesieve-client.h

src/managesieve/managesieve-quota.c