meta: Extract common pull/reload flow, use git hook.

Instead of checking for changes, via comparing version hashes, use the
hook mechanic of git.

We still want to be able to trigger the functionality by hand, hence we
encapsulate functionality into seperate function. And made them callable
via parameters. Now we can call for pull or just reload. Which wasn't
possible before.

For further reusability we extract the script flow.
fastd: Use git hook for change detection.

Also apply just emerged flow abstraction and rename autoupdate_fastd_keys into update-fastd-keys.
named: Convert custom zones update into common update script format.
alfred: start batadv-vis
firewall: introduce rate limiting support
firewall: Add rate limit support to service type.
ntp: Activate rate limiting in firewall rule.

Rate limit the amount of connection to 10 in one hour.
Merge pull request #32 from sargon/batadv-vis

alfred: start batadv-vis
Merge pull request #33 from sargon/firewall-rate-limit

Firewall rate limit
sshd: rate limit to 3 per 60s
Merge pull request #24 from sargon/refactor-repo-pulls

Refacter and Extend repository update handling
routing: remove unreachable defaults from mesh table (42)

as we always have two rules (lookup mesh and unreachable) one after another,
the unreachable default route in the mesh table (42) shouln't be needed anymore
firewall4: first implementation of bcp38 ingress filtering

this has to be applied manually, as the firewall manifest does not
overwrite the 200-block-ranges file when puppet is re-run (change that?)

please note that this is a first version, not complete. We should
also implement this for incoming traffic on the vpn interface?
firewall6: first implementation of ingress filtering

TODO: also for ipv6 uplink...
Merge pull request #35 from ohrensessel/ease-routing

routing: remove unreachable defaults from mesh table (42)
Merge pull request #34 from ohrensessel/rate-limit-ssh

sshd: rate limit to 3 per 60s
Merge pull request #38 from ohrensessel/implement-bcp38

firewall4: first implementation of bcp38 ingress filtering
firewall: Move bcp38 ingress filter into own file
firewall: reinstate block ranges file
firewall: Rollout ingress filter