`libp2p` and `discv5` logfiles are not created with restricted permissions

[macladson]

When constructing the libp2p and discv5 logfiles we do not follow the value of config.is_restricted (which defaults to true). As such the logfiles directory looks like this:

Permissions Size User Date Modified Name
.rw-------  521k mac  19 Mar 19:35  beacon.log
.rw-r--r--  935k mac  19 Mar 19:35  discv5.log
.rw-r--r--     0 mac  19 Mar 19:34  libp2p.log

While I do not believe there anything very sensitive in these particular logfiles, I believe it would be good practice to follow config.is_restricted for these logfiles as well.

Note that the related issue about rotation will affect these files as well, so refer to #7170