Fix Token Transfer unit conversion for decimal value

[VagPanour]

Some tokens (i.e. iUSDT or iUSDC) use a 6 decimal conversion value instead of 18 (standard for most tokens). A fix is needed in order the key 'value_decimal' to return the correct decimal value in both cases. Example below

.

[pthirun]

use redis to cache

[robcxyz]

Going to require a backfill