- `HEALTH_TARGET_ADDRESS` to replace `HEALTH_ADDRESS_TO_PING`
- Remove `github.com/go-ping/ping` dependency
- Dial TCP the target address, appending `:443` if port is not set
- Better settings tree structure logged using `qdm12/gotree`
- Read settings from environment variables, then files, then secret files
- Settings methods to default them, merge them and override them
- `DNS_PLAINTEXT_ADDRESS` default changed to `127.0.0.1` to use DoT. Warning added if set to something else.
- `HTTPPROXY_LISTENING_ADDRESS` instead of `HTTPPROXY_PORT` (with retro-compatibility)
- `HEALTH_OPENVPN_DURATION_INITIAL` renamed to `HEALTH_VPN_DURATION_INITIAL` with retro-compatiblity
- `HEALTH_OPENVPN_DURATION_ADDITION` renamed to `HEALTH_VPN_DURATION_ADDITION` with retro-compatiblity
- Order of threads to shutdown (control then tickers then health etc.)
- Rely on closing channels instead of waitgroups
- Move exit logs from each package to the shutdown package
