Add Vec of lot_num's field to ActionRecord, so the AR knows which lots it is in.

[scoobybejesus]

There is an Impl ActionRecord that iterates over all Lots (of its Account) to find the Movements the ActionRecord begat. It may be wise to cache lot_num values (which are cached in the Movements already) in a new ActionRecord field.

The fn is called several times throughout the code. This could save a lot of searching, particularly in cases where the number of lots is extremely large.

[scoobybejesus]

Though doable, the problem is that an ActionRecord is an immutable struct. This means we'd need to use some means of later pushing to the Vec. Two options are:

• Cell<Vec<u32>>
• RefCell<Vec<u32>>

Both of these arguably cause more programmer cognitive load than would be gained in additional performance. Though an apples vs oranges comparison, a relevant one. Will leave the issue open for now anyway.