DNS/proxy settings, when missing from configuration, fall back to
whatever the server pushes.
With isDNSEnabled/isProxyEnabled it's now possible to override this
behavior.
- Treat empty passphrase as no passphrase
- Parse authentication requirement from --auth-user-pass
- Overload ConfigurationParser with String parameter
- Move OpenVPN fallbacks inline with builder
Give a withFallbacks: option to initialize basic fields rather
than leaving them nil.
Minimize target dependency on OpenSSL (easier to drop later).
Outside of OpenVPN tunnel extension, OpenSSL is only used to
decrypt encrypted private keys in CryptoContainer (found in
TunnelKitOpenVPNCore, therefore "temporarily" dependent on
CTunnelKitOpenVPNAppExtension for TLSBox/CryptoBox).
Davide De Rosa