**What**
- journald log provider using exec to journalctl
```
journalctl -t <namespace>:<name> --output=json --since=<timestamp> <--follow> --output-fields=SYSLOG_IDENTIFIER,MESSAGE,_PID,_SOURCE_REALTIME_TIMESTAMP
```
- This can be tested manually using `faas-cli logs` as normal, e.g.
`faas-cli logs nodeinfo` should tail the last 5 mins of logs.
- Very basic tests ensuring that the `journalctl` comamand is correctly
construction and that the json log entrys are parsed correctly.
- Add simple e2e test to grep the function logs
Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>
This patch completes part of the work in #20 by porting the code
for faas-containerd in-tree. When tested, I was able to deploy
and then remove figlet from the store on `x86_64`.
In a follow-up PR, duplication will be removed where possible
and consolidated with updated documentation.
Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
