Fix/moved mag reset outside of constructor

[yyaatt0]

I removed the reset_mag() call inside the icm constructor because after a icm reset, the i2c master may not be ready. For a reliable and consistent startup of the icm device, reseting the mag outside of the constructor consistently works. Also included the reset_mag() call in the demo file as an example of how to use the driver.

Note: I have tried polling until the i2c master is ready, but still did not work.

Resolves #32

[kammce]

Thank you so much for the PR. from reviewing this, I think I see what's needed. You brought out the logic for resetting and initializing the driver on the outside so you could control how much time elapses before each step. What this tells me is that the constructor for the driver actually needs a steady_clock passed into it so it can delay the necessary amount of time. Otherwise, we put the burden on the developer using this driver:

1. To remember to initialize these in the right order
2. To delay the right amount between messages.

So what we should do is add that new constructor that takes a steady clock by reference and put a [[deprecated(message)]] attribute on the old constructor. That way people get a warning to not use it since it's dangerous.

Thank you again for taking this on.

[yyaatt0]

I've added the depreciated attribute to the old constructor as well as passing steady clock into the icm. I also needed to add helper functions to help allow time and ensure i2c is ready during the reset calls; specifically mag_whoami_ok() and reset_i2c_master().

If there are any critiques, let me know and I'll update accordingly.

[kammce]

Do we need the steady clock after initialization? If not, then there is no need for us to hold the steady clock as a member.

[kammce]

Going to merge this now as we have things to fix on the CI side for sensor.