Small hotfix for start game balance issues — Convoy Steam update #342107

Since adding shields to the items enemies can have at low tiers, it was a bit too difficult at start game. The following changes have been made to fix this: The default layout has been changed. The Sidewinder was switched for a Bobcat with a utility slot The default MCV now has an EMP gun instead of a mine thrower The Shield Mk1 now negates 100 HP instead of 150 The repair drone now has a cost value again! Some typos in scenarios were fixed