create multiple line charts

[dunland]

As stated by cqx931 in the code these links provide an example for line graphs in d3.js:
https://www.d3-graph-gallery.com/graph/line_smallmultiple.html
https://bl.ocks.org/tomshanley/b841837f5414b34b7c45055d97e7674d

the graphs should contain data of cost development vs time. data can be generic, first, and should be in csv style, since this is likely to be the format of the data as provided by the abm simulations later.

[dunland]

• check whether the json-output of the fake simulation in the frontend has the right format

semantically useful plots

fake simulation (frontend, @dunland )

• step = GAMA-time-step (day?)
• add global val: heat_grid_cost ↑/step

or, even better: create API from GAMA!

infoscreen, @kazux2

• cost-vs-time-graph: heat_grid_cost and investment_cost as f(x)