* Allow passing negative numbers to specify partition boundary relative to disk end
Fixes: https://github.com/ansible/ansible/issues/43369
* parted: unit test case, create partition with part_start: -1GiB
* fs_type parameter is not really optional for negative part_start parameter
* Revert "fs_type parameter is not really optional for negative part_start parameter"
This reverts commit 800b1cb00b.
Instead: added notes and documentation about netagive part_start and fs_type.
* include fs_type in negative part_start example
