added D.va and Winston buffs

Balanced some supports that weren't very fun to play as.

Brigitte:

damage at 150%
healing dealt at 30%

Lucio:

Damage at 175%

Mercy:

Damage at 150%
Healing dealt at 125%

Ana:

Damage at 175%

Moira:

Damage at 150%
Healing dealt at 50%