fix misleading comments and names for error rate and error ratio

[zigen]

Describe the bug https://github.com/sfc-aqua/quisp/blob/b867daa806f3ecae72e866727764c6caf42502c5/quisp/networks/omnetpp.ini#L107 these values are rates. this must be fixed. and used it here https://github.com/sfc-aqua/quisp/blob/b867daa806f3ecae72e866727764c6caf42502c5/quisp/channels/QuantumChannel.cc#L112-L119

In StationaryQubit, gate errors are described as ratios and memory errors are described as rates. https://github.com/sfc-aqua/quisp/blob/b867daa806f3ecae72e866727764c6caf42502c5/quisp/networks/omnetpp.ini#L46-L85

I don't know whether we should unify to "rate" or "ratio" or leave it.