Replace ctrl/attr.cfg (customized text colors/attrs) with ctrl/attr.ini

Another legacy config file replaced with .ini file (for easier editing and
future extensibility).

No longer dynamically allocate scfg_t.colors (no need). There's really no
reason why this is still an array, but leave as is for now.

Also, I noticed JS console.color_list (also an array) is not enumerable
(or documented) - that should be fixed.