MAINT: deprecate json ROQ weight format

The longest (by a long way) two tests in the unit tests are reading and writing the json ROQ weights. These are something of a historical aberration that use a huge amount of memory and time to read and write. I propose we deprecate and remove this functionality in the next to minor releases.

added <10 lines Infrastructure Refactoring labels

I also suspect that these jobs are the source of random failures of the unit testing. I think that the large memory usage leads to the tasks getting killed.

approved this merge request

changed milestone to %2.1.0

approved this merge request

mentioned in commit 8ed276d0

merged