Ecl2df

Bugfix for WELOPEN and COMPDAT when keyword order within one date matters.

Feature addition:
* The compdat module now also parses WELOPEN keywords.

Deprecations:
* Functions that have emitted DeprecationWarnings for at least 9 months are now removed. This affects both API and command line endpoints.

Add ECL2CSV and CSV2ECL as ERT forward models.

* rft module now supports well topology emitted by WellBuilder. The rft module is fully refactored, potentially new set of bugs present.
* Improved error handling in tran, nnc and equil.

* New module: pvt. Parses PVT data, and can also write PVT include files from dataframes
* equil module supports more keywords, and can write include files from dataframes
* satfunc module can write include files.
* Documentation upgrade, dedicated pages for most modules
* grid module can export grid parameters to include files
* nnc module can write EDITNNC data
* Py3 bugfix for gruptree
* Refactored dataframe parsing from deck, easing addition of support for more keywords.

Bugfix release.

* Changes necessary to work with opm-common testing/2020.3/rc1.

Bonus feature addition: equil.df has added the EQLNUM column.