Also enables support for Alpine post-upgrade script with warning
if it's necessary to run update-conf to apply new version of files
in /etc:
```
...
Executing one-context-6.1.80-r0.20210809gitbcd3c5b.post-upgrade
WARNING: Run update-conf to process any updated one-context files in /etc!
Executing busybox-1.33.1-r2.trigger
Executing eudev-3.2.10-r0.trigger
OK: 148 MiB in 118 packages
$ update-conf -l
//etc/one-context.d/loc-09-timezone
//etc/one-context.d/loc-30-console
//etc/one-context.d/loc-10-network
//etc/one-context.d/loc-16-gen-env
```
Closes#163
* BSD context
* BSD service scripts
* Added ToDo
* Add context scripts
* Freebsd packaging
* Freebsd packaging finished
* Rollback OS detection
* Fix bug with default gateway configuration
* Add services for pfsense
* Remove bsd context script
* Replace /bin/bash with /usr/bin/env bash
* Remove /bin/bash symlink creation
* Fix service naming
* Replace /bin/bash for /bin/sh on BSD service scripts
* Fix hardcoded cdrom drive
* Fix service start on boot bug on pfsense
* Fix bug when creating new users
* Fix bud with sudo
* Fix bug with crypted passwords
* Fix bug with hostname
* Fix sed bug related to hostname
* Fix bug with domains
* Fixed bug: variable should be local