Remove deprecated flags in prep for v6.0.0 (#6490)

* Delete previously deprecated flags

* Update CLI docs

* Remove deprecated BN flags

* Use ethereum-package main branch

* Delete env_log/-l

book/src/help_general.md

@@ -122,9 +122,6 @@ Flags:
           debugging specific memory allocation issues.
   -h, --help
           Prints help information
-  -l
-          DEPRECATED Enables environment logging giving access to sub-protocol
-          logs such as discv5 and libp2p
       --log-color
           Force outputting colors when emitting logs to the terminal.
       --logfile-compress