[Feature] Support `helmfile` as a deployment target

[saw-jan]

It would be awesome to have an option to run the deployment using helmfile for projects that use it to manage the charts for different environments. 🥹

Possible config parameters could be:

• deployment_target: helmfile - to run helmfile sync
• app_path: . - repo path where helmfile.yaml is located
• helmfile_options: -e test - to provide helmfile sync command options. Final command: helmfile sync -e test
• proxy_tls: traefik:80 - same as helm
• proxy_tls_hosts: ... - same as helm