Adding thermal building component

[Maxhi77]

Hello,

I am working on a thermal building model. With that the internal temperature of the building can be optimized within temperature boundaries. The focus is on residential buildings. The thermal building model is connected to a european wide and public building data bank.

When I am done, I will make a pull request.

I added the issue out of two reasons:

• to avoid identical work
• questions about use of building model before pull-request is finished

[Maxhi77]

I had a discussion with @p-snft about the right place for the building component. It might be more logical to integrate the building component with API to the building database in oemof.thermal. The reason for this is that the output of the building class is linked to a predefined unit. Currently the output is a heating or cooling demand in watts.

Inputparameters:

[Maxhi77]

#985

[p-snft]

This should be closed when #985 is merged.