base existential deposit on price of DOT

I believe we should set the existential deposit to change once a month based on the price of DOT.

We could average the cost in fiat such as DOTUSD, DOTAUD, DOTEUR, and DOTGBP and set it to a value such as $5 worth of dot, compared to that average.

As the price of DOT goes up, unless somehow limited, it will make it impossible for people to have an account without first depositing $100+ without either lowering or somehow changing how existential deposit works.

Thoughts, or more to add on?