Add package absent state

app/classes/state/os/PackageAbsentState.js

@@ -0,0 +1,24 @@
+const State = require('../State')
+
+class PackageAbsentState extends State {
+    constructor(host, config) {
+        if ( !host.packages ) {
+            throw new Error(`Cannot apply package absent state to host ${host.name}: missing package manager API.`)
+        }
+        super(host, config)
+    }
+
+    async reverse() {
+        return this._host.packages.install(this._config.package)
+    }
+
+    async check() {
+        return !(await this._host.packages.is_installed(this._config.package))
+    }
+
+    async apply() {
+        return this._host.packages.uninstall(this._config.package)
+    }
+}
+
+module.exports = exports = PackageAbsentState