[OUR LAND] Define Datasets and Data Releases for set of data

[KhadijaMahanga]

Different data set on our_land such as agricultural sales statistic and DRDLR report to be defined to a datasets and have release year.

[KhadijaMahanga]

This issue depends on an update of HURUmap-apps' wazimap package to include datasets releases. wazimap-za, a similar project, are using the 'git+https://github.com/OpenUpSA/wazimap.git@releases#egg=wazimap[gdal]' version of wazimap which include dataset and releases

[kilemensi]

Migrated to PT.