Show defined category and tier prices in the admin listings

The Categories listing (Categories of a resource) and the Tiers listing (Tiers of a slot) under yoyaku_ui show label, key and capacity, but no price. An operator cannot see what each category or tier defines without opening its edit form.

Add a Price column to both listings, populated by yoyaku_payment so yoyaku_ui keeps no dependency on payment. The column shows the price defined on the row itself, not the final resolved price: a category's own price, or a tier's price override. Where the row defines none (a category that inherits its payment block, a tier with no override) it reads "Inherited", so a resource manager sees at a glance where a price is set and where it comes from elsewhere. The final resolved price a booker pays stays on the booking and place-map pages.

Approach:

• yoyaku_ui builds each admin table with its row entities available and invokes an alter, hook_yoyaku_ui_entity_table_alter, so any module can add a column.
• yoyaku_payment implements the alter to add the Price column, reading the entity own price or override field.

Related to #3612687: the resolved price shown to bookers is a separate concern handled there.