Add new columns to price database to keep informations about the source of the price.

[provinzio]

possible columns:

• source_utc_time (from when is the price)

• source (from where is the price)

• remark general remark column, but would be better to have more specific columns

• write patch to add these columns to database, when patch is done print warning which reccommend to refetch all prices

• update set price db function to require more arguments