Split off cli into separate binaries (#37)

* 🎨 Split off cli into separate binaries

This commit splits off the cli into 3 binaries:
- agent
- cli
- provider

The provider now is a separate component that can be tested by itself
and have its own lifecycle. This paves the way to a ligher c3os variant,
HA support and other features that can be provided on runtime.

This is working, but still there are low hanging fruit to care about.

Fixes #14

* 🤖 Add provider bin to releases

* ⚙️ Handle signals

* ⚙️ Reduce buildsize footprint

* 🎨 Scan for providers also in /system/providers

* 🤖 Run goreleaser

* 🎨 Refactoring

internal/utils/strings.go

@@ -0,0 +1,20 @@
+package utils
+
+import (
+	"math/rand"
+	"time"
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+func RandStringRunes(n int) string {
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letterRunes[rand.Intn(len(letterRunes))]
+	}
+	return string(b)
+}