Add units and scale information to channels

[bparks13]

In the channel information, we can add information such as the units of the channel, and its valid range. Currently this is not used by the LFP Viewer, but there are plans to use this information to ensure that the channels do not saturate.

This is especially useful for channels like the BNO data streams, where we have Euler angles, quaternion, temperature, etc. all with different ranges and units.

For context, this came from this issue.

[bparks13]

@aacuevas @jsiegle I'm working on adding the range information to all channels in this plugin, and I was hoping to get some feedback on the proposed ranges to see if they are reasonable, as well as to get a sense of how they will be used in the future. I know that right now the InputRange is not used, but I want these in place so that we can take advantage of the update as soon as it comes out.

Proposed ranges for device streams

Note that all min/max values are floats in the GUI API:

Device - Stream	Minimum	Maximum	Units
AnalogIO - Analog input	-10	10	Volts
BNO055 - Euler.Yaw	0	360	Degrees
BNO055 - Euler.Roll	-180	180	Degrees
BNO055 - Euler.Pitch	-90	90	Degrees
BNO055 - Quaternion	-1	1	unitless
BNO055 - Acceleration*	-100	100	m/s^2
BNO055 - Gravity	-10	10	m/s^2
BNO055 - Temperature	0	100	Celsius
BNO055 - Calibration	0	3	unitless (integers)
DigitalIO - Inputs/Buttons	0	1	unitless (binary)
HarpSyncInput - Time*	0	1000	Seconds
MemoryMonitor - PercentUsed	0	100	%

* These streams I am not sure what a good range should be. I gave my best guess as to what a valid range is, but I am open to suggestions.

[jsiegle]

I would not specify values for the Neuropixels streams -- the input range for 1.0 probes will depend on the gain settings, and we don't actually want the display to auto-scale for ephys data (since the default range already works well).