map validation suggestion

[illwieckz]

One thing we may want to validate is map dpk.

If we don't decide to avoid delta paks for maps,

for every map-name_version.dpk, if there is a maps/name.bsp file:

• maps/name.map file,
• maps/name/lm_*.webp files, at least two, always even (light map + deluxe map),
• minimaps/name.minimap file
• minimaps/name.crn file

If we decide to avoid delta paks for maps,

for every map-name_version.dpk:

• maps/name.bsp file,
• maps/name.map file,
• maps/name/lm_*.webp files, at least two, always even (light map + deluxe map),
• minimaps/name.minimap file
• minimaps/name.crn file
• meta/name/name.arena file
• meta/name/name.crn file

[illwieckz]

I updated the list above, especially I removed navmeshes from the list.

[slipher]

If we want to support delta paks for maps we would need to fix Unvanquished/Unvanquished#2225.