Fix a mistake in initialization of temperature in Crocus and add option to initialize glacier temperature in namelist

[trudeeidhammer]

Expected Behavior

The initial temperature in Glaciers when using Crocus was intended to be just below freezing.
Furthermore, glaciers in different locations can have different temperatures. I suggest adding the ability to specify glacier temperature in namelist.

Current Behavior

The current way of calculating initial temperature is hardcoded and a mistake causes the temperature to be initialized at zero degree Celsius.
Furthermore, the current equation is adhoc, and a more physical correct equation is available.

Possible Solution

Use the correct physical equation to calculate initial glacier temperature
Add the option to set the initialize glacier temperature in namelist.

Steps to Reproduce (for bugs)

Your Environment

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