Implement localisation for custom_attributes

[maxice8]

Example government file:

imperium_of_mann_reform = {
	icon = imperium_mann
	allow_normal_conversion = no
	lock_level_when_selected = yes
	allow_convert = no
	fixed_rank = 3
	potential = {
		has_country_flag = imperium_mann_flag
	}
	valid_for_nation_designer = no

	modifiers = {
		global_unrest = -2
		max_absolutism = 10
		monarch_military_power = 2
		cav_to_inf_ratio = 0.5
	}
	
	custom_attributes = {
		locked_government_type = yes
	}

	conditional = {
		allow = { has_dlc = "Third Rome" }
		claim_states = yes
	}
}

The file in the cwtools-rule is common/government_and_reforms