sparkles: state api sdk (#262)

* ✨ Add state api

This is related to https://github.com/kairos-io/kairos/issues/34.

Starts to unify the API to retrieve the state in the sdk to have a common place to query system status information.

* 🤖 Add test

* Update go.mod

* ⚙️ Fine-tune detection of partitions

* 🤖 Add more fine-grained tests

* 🎨 Add /dev/ to partition name

* 🤖 Fixup tests

* ⚙️ Remount accessors

* ✨ Add state partition to cloud-init paths

* 📝 Upper case Kairos in motd

* 🎨 Add mounts sdk

* 🎨 Set grub options via SDK

* 🎨 Make it more idiomatic

sdk/system/options.go

@@ -0,0 +1,30 @@
+package system
+
+import (
+	"github.com/hashicorp/go-multierror"
+)
+
+type Changeset []func() error
+
+func (c *Changeset) Add(f func() error) {
+	*c = append(*c, f)
+}
+
+type Option func(c *Changeset) error
+
+func Apply(opts ...Option) error {
+
+	c := &Changeset{}
+	for _, o := range opts {
+		if err := o(c); err != nil {
+			return err
+		}
+	}
+
+	var err error
+	for _, f := range *c {
+		err = multierror.Append(f())
+	}
+
+	return err
+}