Rewrite of the entrypoint in Golang (#71)

- General improvements
    - Parallel download of only needed files at start
    - Prettier console output with all streams merged (openvpn, unbound, shadowsocks etc.)
    - Simplified Docker final image
    - Faster bootup
- DNS over TLS
    - Finer grain blocking at DNS level: malicious, ads and surveillance
    - Choose your DNS over TLS providers
    - Ability to use multiple DNS over TLS providers for DNS split horizon
    - Environment variables for DNS logging
    - DNS block lists needed are downloaded and built automatically at start, in parallel
- PIA
    - A random region is selected if the REGION parameter is left empty (thanks @rorph for your PR)
    - Routing and iptables adjusted so it can work as a Kubernetes pod sidecar (thanks @rorph for your PR)

internal/params/params.go

@@ -0,0 +1,73 @@
+package params
+
+import (
+	"net"
+	"os"
+
+	"github.com/qdm12/golibs/logging"
+	libparams "github.com/qdm12/golibs/params"
+	"github.com/qdm12/golibs/verification"
+	"github.com/qdm12/private-internet-access-docker/internal/models"
+)
+
+// ParamsReader contains methods to obtain parameters
+type ParamsReader interface {
+	// DNS over TLS getters
+	GetDNSOverTLS() (DNSOverTLS bool, err error)
+	GetDNSOverTLSProviders() (providers []models.DNSProvider, err error)
+	GetDNSOverTLSVerbosity() (verbosityLevel uint8, err error)
+	GetDNSOverTLSVerbosityDetails() (verbosityDetailsLevel uint8, err error)
+	GetDNSOverTLSValidationLogLevel() (validationLogLevel uint8, err error)
+	GetDNSMaliciousBlocking() (blocking bool, err error)
+	GetDNSSurveillanceBlocking() (blocking bool, err error)
+	GetDNSAdsBlocking() (blocking bool, err error)
+	GetDNSUnblockedHostnames() (hostnames []string, err error)
+
+	// Firewall getters
+	GetExtraSubnets() (extraSubnets []net.IPNet, err error)
+
+	// VPN getters
+	GetNetworkProtocol() (protocol models.NetworkProtocol, err error)
+
+	// PIA getters
+	GetUser() (s string, err error)
+	GetPassword() (s string, err error)
+	GetPortForwarding() (activated bool, err error)
+	GetPortForwardingStatusFilepath() (filepath models.Filepath, err error)
+	GetPIAEncryption() (models.PIAEncryption, error)
+	GetPIARegion() (models.PIARegion, error)
+
+	// Shadowsocks getters
+	GetShadowSocks() (activated bool, err error)
+	GetShadowSocksLog() (activated bool, err error)
+	GetShadowSocksPort() (port uint16, err error)
+	GetShadowSocksPassword() (password string, err error)
+
+	// Tinyproxy getters
+	GetTinyProxy() (activated bool, err error)
+	GetTinyProxyLog() (models.TinyProxyLogLevel, error)
+	GetTinyProxyPort() (port uint16, err error)
+	GetTinyProxyUser() (user string, err error)
+	GetTinyProxyPassword() (password string, err error)
+
+	// Version getters
+	GetVersion() string
+	GetBuildDate() string
+	GetVcsRef() string
+}
+
+type paramsReader struct {
+	envParams libparams.EnvParams
+	logger    logging.Logger
+	verifier  verification.Verifier
+	unsetEnv  func(key string) error
+}
+
+func NewParamsReader(logger logging.Logger) ParamsReader {
+	return &paramsReader{
+		envParams: libparams.NewEnvParams(),
+		logger:    logger,
+		verifier:  verification.NewVerifier(),
+		unsetEnv:  os.Unsetenv,
+	}
+}