upkeep: in abcd_demo, rename abcd_timestamp to ald_timestamp

[jdhoffa]

In #315 , the abcd_demo dataset had the ald_timestamp column renamed to abcd_timestamp.

Unfortunately, the abcd data as Asset Impact distributes it still contains the name ald_timestamp.

When pressed on this topic, Asset Impact was worried the breaking change of changing a column name might impact users existing workflows, and were hesitant to do so.

We should align the column name with what is in the expected dataset.

Alternatively, we could remove the column entirely (relates to #257 ), as I don't believe it is a critical column in any of the pacta.* or r2dii.* code:
https://github.com/search?q=org%3ARMI-PACTA%20ald_timestamp&type=code
https://github.com/search?q=org%3ARMI-PACTA+abcd_timestamp&type=code

FYI @jacobvjk

[jacobvjk]

I would almost opt to go for #257 and remove all the variables you identified as not crucial @jdhoffa. I think it is fair explain that other variables can be added and what for. e.g. intermediate parent for the unlikely case that someone has this kind of ownership data. Or project finance flag for.. well what exactly? In the end, this is where it can be good to link to documentation explaining the new variable grouping of pacta.multi.loanbook.*

[jdhoffa]

I back it! Go for it