Adds configuration yaml support, using a simple config yaml containing the previously hardcoded values:
```
library_path: /path/to/core/src/opnsense/site-python
flowd_source: /path/to/flowd.log
database_dir: /path/to/netflow
pid_filename: /path/to/netflow.pid
```
Startup using local config, using:
```
flowd_aggregate.py -c my_config.yaml --console
```
Further then path relocations, this commit should not contain any new features. The other scripts, not related to the daemon have not been altered (yet)
