Add datetime.conf option to disable inferred qualified date ranges, a heuristic that converts certain year-based date ranges into early/mid/late century text. Ex. "late 20th century" is inferred to be 1980 - 1999.
The date parser will convert "late 20th century" to 1980 - 1999 for storage, and will convert the stored 1980 - 1999 range back to "late 20th century" when generating display text.
This datetime.conf option implemented for this issue should disable display text output of inferred ranges. That is, early/mid/late ranges should parse regardless, but text output should not use early/mid/late ranges if the option is set.