Update chailove.md

Update ChaiLove documentation URL.

Update ISSUE_TEMPLATE.md

Minor change.

Update softpatching.md

Add core compatibility section.

Update mkdocs.yml. Move neko_project_ii.md

Remove Neko Project II from mkdocs.yml and move the doc to legacy directory.
Kai is the better core so the regular one doesn't need a doc.

Update mkdocs.yml

Sort cores.

Update remote_retropad.md

Adjust wording.

Update licenses.md

Add Dummy core license URL.

Update gearboy.md

Minor change.

Update retroachievements.md, nestopia_ue.md

Nestopa UE supports achievements now.

Update nside_balanced.md

Update issue tracker URL.

Update yabause.md, todo.md

Sync Yabause with Core Template. Update its To-Do section.