Using a TeX command for the cipherstring instead of a perlscript, structure cleanup and unification & UTF-8

Replaced the perlify.pl Skript by a TeX Command. To achieve this, we have to do some tricks like a grey box behind the listings and explicitly allowing breaks without a hyphen.

Webserver: cleanup, Strict-Transport-Security unified
other practical-settings sections converted to use sectioning instead of descriptions

I hope everbody is content with this fix :)