proxmox-rrd: move unshipped cli tool to examples

proxmox-rrd: move unshipped cli tool to examples

it's a rather low-level tool mostly useful for debugging and some of
it is rather "dumb" (by design) anyway, e.g., it does not
transparently applies journal but really only operates on the DB
files as is (which can conflict with daemon operations).

In summary, not (yet) a tool meant for end user consumption.
Move it to examples folder to avoid compilation on packaging (we do
not ship it anyway) which allows us to move the rather expensive
proxmox-router (pulls in hyper) to the dev-dependencies section.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>