Remove datav3, dfrcv0, dfrcv1 datasets

[TheRealGioviok]

Passed STC

Test  | no_old_data
Elo   | 4.00 +- 2.65 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=16MB
LLR   | 2.97 (-2.94, 2.94) [0.00, 3.00]
Games | N: 22040 W: 5572 L: 5318 D: 11150
Penta | [238, 2578, 5156, 2788, 260]

https://ob.cwchess.org/test/1181/

Passed LTC

Test  | no_old_data
Elo   | 3.59 +- 2.41 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=64MB
LLR   | 2.95 (-2.94, 2.94) [0.00, 3.00]
Games | N: 22630 W: 5405 L: 5171 D: 12054
Penta | [109, 2643, 5589, 2853, 121]

https://ob.cwchess.org/test/1182/

Bench: 18127587