Add script to extract CO2 tables from NIST website
This MR provides a python script, which can create CO2 tables, like the one used in the CO2 test. The tables contain density and enthalpy values for a specified temperature and pressure range. The CO2 tables are created by the help of a website (https://webbook.nist.gov/chemistry/fluid), which calculate the needed values. The query for the values is automated by the python script, which also does the formatting of the received values.
The former way to generate the CO2 table was a Fortran script, which can't be published due to copy right issues. Therefore it was decided in #690 (closed) to use the NIST website and a python script to generate the new CO2 tables. Both approaches use the formula of Span and Wagner to calculate the values and produce the same result (within a acceptable tolerance). The new approach has the advantage, that we can publish the script.