Explain quota change limits

[Krock21]

When trying to change quota on accounts page, I see an error This value must be >= X.

This can be confusing (and was confusing) since there is no explanation on why this limit was enforced. In my case it was enforced by limit from children account and by usage

Also it is hard to understand where the number X comes from. From this code I see some non-trivial logic

I suggest adding (i) icon next to an error with an explanation, like:

• Hardcode limit
• Children limits add up to X
• Usage is X