Add hint about wrong metric units

[begonaalvarezd]

Task description

Because of the many unit and decimal changes that happened, there is a misalignment between the ledger app and the rebased formatting

So what before was named MIOTA now is named IOTA, but also because now Rebased has 9 decimals and before it had 6, ledger is getting amounts with 9 decimals and formatting the units wrongly. Hence we have to show the user a hint about the units: Before Gi --> Now IOTA, and this applies to all metric units, so we should just write a quick table with the unit conversion