Update the PolynomialCompressor API to allow entering the envelope space

[fwitte]

Right now, the data for condensation and evaporation temperature have to be rectangular, meaning a grid is created over the range of condensation and evaporation temperature. Instead, it should be possible to create a grid of points that are only within the specified envelope.

For that, two entry points are possible:

1. Envelope + Polynomials

• The envelope is defined via the outside nodes
• A grid of datapoints is generated inside the envelope
• The polynomials are evaluated to get a lookuptable (x1, x2): power/cooling

2. Power/cooling data with respective x1 and x2 (this can be generated from 1)

• For all pairs of x1 and x2 (either directly from datasheet or via the evaluated polynomials from 1) the efficiency polynomials are fitted to the data