An URI containing a bracketed or non-bracketed IPv6 address of the form
http://[::1]:42 was previously split on the first colon for port extraction,
causing a subsequent to_count() call to fail. Harden this to check for a
digits in the last :[0-9]+ component.
Fixes#4842
This also installs symlinks from "zeek" and "bro-config" to a wrapper
script that prints a deprecation warning.
The btests pass, but this is still WIP. broctl renaming is still
missing.
#239