Unify Random/Skirmish/Scenario maps

[elexis]

It seems every map type wants to support one thing that only the other maptype support.

• Skirmish and random maps want to be able to lockdown some settings like Scenario maps can do.
• Random maps want to be able to come with default but changeable settings like Skirmish maps do.
• Scenario and skirmish maps might want to run mapgen code on the entities and textures before the gamestart, like random maps do.
• Scenario and skirmish maps might want to use a "Random map" option too (i.e. a random map is chosen at gamestart), like random maps do.

Random maps only support that, because they are kept compatible to any user-given setting and do not provide any defaults.

If that trait is lost, then the "Random map" item has to pick one of the maps that supports all the user-given values.

For example if a map locks the number of players to 2, but there are 3 players assigned while the "random map" item is selected. So only maps that support three players can be chosen randomly.

Same support would have to be added to all gamesettings.

So it seems the "maptype" property will have lost it's technical meaning entirely once everything supports everything else? Then one can consider removing it in order to reduce code complexity and lead developers to implement every feature agnostic of some maptype property.

• The original meaning of the maptype must have been "fixed content maps" vs. atlas maps with chosable civs and "randomly generated maps". This meaning can still be transported with the tags system (Keywords).

• Some kind of non-technical map-grouping system for campaigns will have to be implemented eventually too.

[elexis]

Closing as won't fix until the premise of the feature description is satisfied (every maptype supports every of the 4-5 mentioned features). (We can still plan ahead here)