Otherwise installation in Docker containers fails with:
```
...
Adding new user `nimbus' (UID 101) with group `nimbus' ...
Not creating home directory `/home/nimbus'.
/var/lib/dpkg/info/nimbus-beacon-node.postinst: 39: systemctl: not found
dpkg: error processing package nimbus-beacon-node (--configure):
installed nimbus-beacon-node package post-installation script subprocess returned error exit status 127
Errors were encountered while processing:
nimbus-beacon-node
E: Sub-process /usr/bin/dpkg returned an error code (1)
```
Signed-off-by: Jakub Sokołowski <jakub@status.im>
* packaging updates
* one package per binary (nimbus_beacon_node, nimbus_validator_client)
* use `-` in package name (`_` is separating the version)
* don't include (un)installation scripts in package
* default metrics port 8108 for vc
* fix several upgrade/install errors in scripts
* add JWT option to service files
* don't attempt to remove user on purge