rate parsing shouldn't use powers of 2

[edwintorok]

According to https://en.wikipedia.org/wiki/Binary_prefix#Data_transmission_and_clock_rates and
https://en.wikipedia.org/wiki/Gigabit_Ethernet a GbE link can transfer 1,000,000,000 bits per second,
and a 100 Mbit/s link can transfer 100,000,000 bits per second.

But you parse 1Gbps as 2^30 which doesn't seem right:
https://github.com/frenetic-lang/ocaml-topology/blob/master/lib/Network_Common.ml#L20

[jnfoster]

Yup. Note that most development now happens in the main frenetic repository