Make the "Stock transactions" page an actual View of transactions

Problem/Motivation

Right now, even though the menu item for "Stock transactions" from the module says it's the place to create and view transactions, it actually only supports creating them. In fact, it goes straight to the transaction add form, which means it probably shouldn't be under "Configuration" at all, but we can defer moving this till later. At the very least, we should see a View of transactions here.

Proposed resolution

This should be a View in reverse chronlogical order showing transaction summaries and also allowing you to filter / navigate through to see all transactions related to another transaction. I'd propose something like the following columns:

1. Transaction ID
2. Short date
3. Product label (linked) with the SKU and product variation label beneath it (e.g., "ABL-XL A Blue Leg X-Large")
4. Warehouse
5. Type
6. Quantity
7. Unit cost
8. Note
9. Operations

This should have sorting enabled on the date and exposed filters for date range, product, product variation, warehouse, and parent transaction ... then an oeprations link to view the full history of transactions related to a particular parent. That needs some more thinking, to be honest, as if you filter only to show all transactions whose "related_tid" field is X, then you don't have the context for that "parent" transaction. Maybe that means we should have a header that only appears when "related_tid" is set and renders the parent transaction details into the header?