Previously, the list of CA certificates was generated with a perl script
which is included in curl. As this script is not very flexible, this commit
refactors the expression to use the python script that Debian uses to
generate their CA certificates from Mozilla's trust store in NSS.
Additionally, an option was added to the cacerts derivation and the
`security.pki` module to blacklist specific CAs.
The `mk-ca-bundle.pl` script manages quite well using only curl but
fails without LWP being present due to a `use` statement. This removes
the Perl import of the LWP library and adds curl as a build input.
This is generated with a more recent version of mk-ca-bundle.pl. The
previous version mistakenly dropped some certificates, like "Verisign
Class 3 Public Primary Certification Authority".
