Add configuration integration with popular firewall management tools.

[Ferroin]

Prompted by discussion in #1203, as well as other issues.

Initial implementation should ideally cover UFW and firewalld, as they are the two most popular options.

UFW config would involve a file with the following contents being put in `/etc/ufw/applications.d/:

[netdata]
title = "Netdata real-time performance monitoring web server"
description = "Netdata agent Web UI and Streaming https://www.netdata.cloud"
ports = 19999/tcp

[netdata-statsd]
title = "Netdata statsd server for APM metrics"
description = "Netdata statsd server https://learn.netdata.cloud/docs/agent/collectors/statsd.plugin"
ports = 8125/tcp|8125/udp

Firewalld config would consist of two files being put in /etc/firewalld/services, one called netdata.xml with the following contents:

<?xml version="1.0" encoding="utf-8"?>
<service>
    <short>Netdata</short>
    <description>Netdata Agent UI and Streaming</description>
    <port protocol="tcp">19999</port>
</service>

And a second one called netdata-statsd.xml with the following contents:

<?xml version="1.0" encoding="utf-8"?>
<service>
    <short>Netdata StatsD</short>
    <description>Netdata StatsD server</description>
    <port protocol="tcp">8125</port>
    <port protocol="udp">8125</port>
</service>

We probably want to unconditionally install these when running the regular installer, but should probably not install them when invoking make install, which means they would need to be handled in netdata-installer.sh, packaging/makeself/install-or-update.sh, contrib/debian/rules and netdata.spec.in.

[ilyam8]

contrib/debian/rules

For debian/rpm the default is "bind to = localhost". Or you mean install those rules, but not (somehow) enable them?

[Ferroin]

This would be installing service definitions, which users could then trivially enable through UFW/firewalld instead of having to manually add the ports if they wanted to bind to something other than localhost.

[ilyam8]

Firewalld config

Added in firewalld/firewalld#948

[Ferroin]

Firewalld config

Added in firewalld/firewalld#948

Oh, nice, that makes this even easier.