Sets saline solution to remove the skill gap so that players don't purpo...

...sefully injure themselves to train the skill. This does not impact any recipes because salt water is always usable as a substitute in them when players just want to use the cooking skill.

Related to https://github.com/CleverRaven/Cataclysm-DDA/pull/9871 but with the first aid level required to learn from books lowered to allow this to function as a transitional recipe.