This request adds an additional logging flag to change the name of the
logfiles produced by erigon to be prefixed by a name other than
'erigon'.
This allows multiple nodes to log to the same directory without
overwriting each others files. It is requires so that the devnet when
running can maintain all of its log files in a single consolidated
directory which survives devnet restarts.
---------
Co-authored-by: Mark Holt <mark@distributed.vision>
