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/version.go

@@ -0,0 +1,20 @@
+package params
+
+import (
+	"github.com/qdm12/golibs/params"
+)
+
+func (p *paramsReader) GetVersion() string {
+	version, _ := p.envParams.GetEnv("VERSION", params.Default("?"))
+	return version
+}
+
+func (p *paramsReader) GetBuildDate() string {
+	buildDate, _ := p.envParams.GetEnv("BUILD_DATE", params.Default("?"))
+	return buildDate
+}
+
+func (p *paramsReader) GetVcsRef() string {
+	buildDate, _ := p.envParams.GetEnv("VCS_REF", params.Default("?"))
+	return buildDate
+}