Update and Merge all git ignores.
Craftable vehicle batteries

New item "lead plate" and recipes for small storage, motorcycle, car,
and truck batteries.
Some Tweaking

Batteries now need water and acid, plates are made with fabrication
skill, battery cases are made with plastic instead of scrap.
booking recipes

Recipes for batteries are learned from electronics books, same as
regular batteries.  Batteries also require fewer cables.
More tweaks

Add fabrication skill to batteries, take longer to build, requires rags.
Adjust plates

Plates are now bigger, need fewer of them to make batteries,.  Also
adjusted crafting time, water-acid mix, added scrap to recipes, and
added decomp_learn to lead plates.
fix random skill selection using skill index as skill ident
add functions to load and store default mod list
Add missing comma

Thanks Rivit for catching this.
Final tweaks

Changed learned from, fixed bugs, altered some values.
add display hint for saving list of active mods as default
Merge branch 'default-flag-for-mods' of https://github.com/BevapDin/Cataclysm-DDA into BevapDin-default-flag-for-mods
Merge pull request #5916 from NaturesWitness/craft-vehicle-batteries

(Ready) Craftable vehicle batteries
Merge branch 'skill-fix' of https://github.com/BevapDin/Cataclysm-DDA into BevapDin-skill-fix
Fixes FileExists check to work with MSVC
Removed commented code.
Merge branch 'fix-file-exists' of https://github.com/macrosblackd/Cataclysm-DDA into macrosblackd-fix-file-exists
Added user-default-mods.json to the ignore list as this is a user setting
Removed comment per macrosblackd's request
Merge branch 'fix-file-exists' of https://github.com/macrosblackd/Cataclysm-DDA into macrosblackd-fix-file-exists