Fix pandas issues

[p-snft]

This PR introduces the following changes:

• Rework generation of time series to allow usage of Pandas >= 1.2
• Require more recent version of dependencies (pandas>=1.0, numpy >= 1.17)
• Split electric and thermal profile generation into two files (helped with debugging)
• Test sums over individual profiles instead of sum over all profiles (still no unit test, but an improvement, see There are no unit tests #35)

[pep8speaks]

Hello @p-snft! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-01-25 15:49:36 UTC

[p-snft]

Setting pandas to < 1.2 might workaround the issue but does not solve it. 1.2 has improved error detection, so our code is probably erroneous:

pandas-dev/pandas#16228

[p-snft]

The decrease in Coverage is actually caused by the dynamic H0 function. As the CI pipeline was broken, however, the decreased coverage was not recognised. In my opinion, the testing should be addressed in another PR.

[p-snft]

A proper solution might be to

1. set index as an ordinary column
2. merge
3. make column from 1 the index.

[p-snft]

I checked that the results of the examples are unchanged. Considering that the last release is actually broken, @uvchik agreed that my self-review this is good enough.