Support editing missing project defines

[GriffinRichards]

Porymap reads a handful of defines that it needs values for. If it fails to find them it enforces a default value:

porymap/src/project.cpp

Lines 28 to 36 in 49cb69f

	int Project::num_tiles_primary = 512;
	int Project::num_tiles_total = 1024;
	int Project::num_metatiles_primary = 512;
	int Project::num_metatiles_total = 1024;
	int Project::num_pals_primary = 6;
	int Project::num_pals_total = 13;
	int Project::max_map_data_size = 10240; // 0x2800
	int Project::default_map_size = 20;
	int Project::max_object_events = 64;

These should be exposed as settings so that users can still set these values without the defines (in case removing them makes sense for their project, e.g. they calculate the value at compile-time some other way). If the defines are parsed the settings can be visible but disabled, with text directing the user to their project file.

I think the real value of doing this is visibility. Unless you dig into the manual it's not clear Porymap will respect changes to these values.