Somehow localize membership type text

[MikaelSiidorow]

Membership type is now stored in the database in a type column with type text:

export const membership = pgTable("membership", {
	id: text("id").primaryKey(),
	type: text("type").notNull(), // TODO: l10n
	/* ... */
});

We could probably do any of the following

1. Keep it as is and don't translate to English
2. Change type to an enum and require code changes to add a new membership type
3. Add another column for type_en for the English translation
4. ...something else?

We also need to be mindful of which is the primary type field, since the current plan is to connect memberships by the type field (renew notifications etc.)