stablecoin api: fetch data pre 2022

[g1nt0ki]

current stablecoin api returns data only post 2022, I think we have data pre 2022, why it is getting cut off and fix it.

Additional quest: optimize code & write to pg as well, and update code to read only from pg.

I found that and removed some filters here: #483 but need to doublecheck there is no other filter anywhere else (I am afraid that there is is, still not able to fetch dai data pre Jan 2021) and need to ensure that the data is correct.