Central threshold configuration

[Solksjaer]

I think it would be a good idea to have a central threshold configuration, which can be referenced on the card config.
This would allowed to reuse those values for any graph you create (I. E.if you have the same temperature graph for different rooms).
Was thinking something like threshold-theme: temperature or threshold-theme: humidity and each theme can be defined in the base code folder.
I have already some threshold defined for that (based on other repos), that I can provide and also if someone has an idea on how to get this started, would love to help coding

[ildar170975]

This idea could be widen up:
-- define a global template(s) with options for color_threasholds, line_width etc
-- use this template for a particular card's instance
-- override a particular option if needed.
In this case it is same as an existing #803.

Meanwhile users may use standard re-use methods like "!include", yaml-anchors & decluttering card (not to mention "!secret" which also does work but is not considered as an appropriate method).