Sample rates in data loading script are off by a factor of 10

[jsiegle]

The example script for loading data lists the sample rates as 3e5 (AP band) and 3e5/12 (LFP band). This should be 3e4 = 30,000 and 3e4/12 = 2500 Hz.

[jsiegle]

Also, the example LFP and AP band gain values should be changed to whatever the defaults are in Bonsai.