Create new enforce_value_in_range config option, disable by default

[TheLastProject]

I've started using bar-card to display the temperature of my house and the desired minimum and maximum temperature. This does, however, mean that the temperature can be outside this range until the house has heated/cooled enough. Because bar-card automatically forces the value to be within the minimum and maximum, this breaks my use case. This small patch fixes it.

I've also disabled this old behaviour by default, because I assume people will generally want to see the real value unless they explicitly mention to want it post-processed to always be within min and max. If you disagree, I'll change the default back to match the old behaviour by default.

Before (true value hidden):

After (true value shown):

[Gluwc]

I've renamed this config option to limit_value.