firewalllog.dat: Add First and Last links, for fast navigation in log lines

Add two links for navigating in log pages, one for going to the
first page and one for goint to the last page.

Introduce variable which points to the first log line to
display on the last possible page.

The commit contains hardcoded text for Last and First, and I
am also uncertain how spaces between links should be handled.
So this should be improved based on feedback.
firewalllog.dat: Use language string for First and Last links
Merge branch 'next' of https://github.com/ipfire/ipfire-2.x into feature_firewalllog_first_last
firewalllog.dat: Use language string for First and Last text
index.cgi: Use language string keys already defined
media.cgi: Use language string keys already defined
qos.cgi: Use language string keys already defined
ovpnmain.cgi: Use language string keys already defined
country.cgi: Use language string keys already defined
firewalllogip.dat: Use language string keys already defined
firewalllogport.dat: Use language string keys already defined
firewalllog.dat: Use language string keys already defined
qos.cgi: Use Language string for legend in graph
media.cgi: htmlcleanup, change <B> tag to <b>, and fix attribute quotation
ids.cgi: htmlcleanup, change html tags from uppercase to lowercase
fireinfo.cgi: htmlcleanup, change html tags from uppercase to lowercase
ovpnmain.cgi: htmlcleanup, change html tags from uppercase to lowercase
pppsetup.cgi: htmlcleanup, change html tags from uppercase to lowercase
remote.cgi: htmlcleanup, change html tags from uppercase to lowercase
services.cgi: htmlcleanup, change html tags from uppercase to lowercase