Add calculation for onion services V2 and V3 traffic graph

The current onion traffic graph says it counts v2+v3 but actually it's missing some v3. As highlighted by Roger in #40036 (closed) before Tor 0.4.6.1-alpha came out, it was. But after that version, it's gotten more complicated.

According to https://metrics.torproject.org/reproducible-metrics.html#onion-services the graph is using the hidserv-rend-relayed-cells line in the extrainfo descriptors.

Up through Tor 0.4.5, this line represented the sum of all onion service cells the relay had seen (v2 and v3). But in commit 3cbc513a (which went into 0.4.6.1-alpha, tpo/core/tor#23126 (closed)) we split it into v2 and v3 counts.

This splits the current onion-service traffic graph horizontally for v2 and v3.