Purpose of change

This fixes some minor issues with missions I spotted while poking around.

Describe the solution

1. Set the chemist mission to actually ask for 100 liters of gasoline, not 500 ml. How did this even happen? 500 does not translate into 100 liters no matter what unit you assume it to be. As mentioned it's half a liter if interpreted as 1 ml each, but if the mission author assumed a unit was a liter that'd be 500 liters, and if assuming they were legacy volume units like water is then it'd be 125 liters.
2. Fixed names of Jesse Issherwood's hunting missions to clarify that you're hunting wolves the first time, with the second mission retaining the "dunno what they are" bit.

Describe alternatives you've considered

I want to also write proper descriptions for more of the missions but figured I'd start with fixes first. Probably need to scrutinize the new missions Zlor ported over more in depth in case we missed any other oversights.

Testing

1. Checked affected files for syntanx and lint errors.
2. Did basic elementary-level math and confirmed that 100000 divided by 1000 equals 100.

Additional context

DDA still asks for half a liter of gasoline: https://github.com/CleverRaven/Cataclysm-DDA/blob/master/data/json/npcs/cabin_chemist/chemist_missions.json#L62

Relevant PR we ported: more NPC locations by @MNG-cataclysm: CleverRaven/Cataclysm-DDA#57483

Checklist