Add #4115: default company colour setting (#6998)

Works only in single player.

src/table/settings.ini

@@ -2755,6 +2755,18 @@ strhelp  = STR_CONFIG_SETTING_LIVERIES_HELPTEXT
 strval   = STR_CONFIG_SETTING_LIVERIES_NONE
 proc     = InvalidateCompanyLiveryWindow
 
+[SDTC_VAR]
+var      = gui.starting_colour
+type     = SLE_UINT8
+flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
+guiflags = SGF_MULTISTRING
+def      = COLOUR_END
+min      = 0
+max      = COLOUR_END
+str      = STR_CONFIG_SETTING_COMPANY_STARTING_COLOUR
+strhelp  = STR_CONFIG_SETTING_COMPANY_STARTING_COLOUR_HELPTEXT
+strval   = STR_COLOUR_DARK_BLUE
+
 [SDTC_BOOL]
 var      = gui.prefer_teamchat
 flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC