Dissipation not shown in tutorials and should be a method

[nikosavola]

If I understand correctly, currently modelling any dissipation requires setting something like

project_info.dissipative['dielectric_surfaces'] = # supply names here

This feels kind of hacky, and is not even shown in the tutorial notebooks. Instead, this is currently seen only in startup_example_script.py and some example scripts

Should there instead be a method in ProjectInfo for selecting dissipative objects? Alternatively, make it an argument for initialisation, something like:

pinfo = epr.ProjectInfo(project_path = path_to_project, 
    project_name = 'pyEPR_tutorial1',
    design_name  = '1. single_transmon',
    dielectric_surfaces = ['si_substrate']
)