Packages feature (#1052)

* Started to work on packages feature

* Added some more validation to packages config

* Fixed some linter warnings

* Updated tests

* Reordered consts to avoid linter error

* Reordered consts to avoid linter error

* Refactored test yaml files to integrate into existing test pipeline

Co-authored-by: Dmitry Berezovsky <dmitry.berezovsky@logicify.com>

tests/test1.yaml

@@ -1,3 +1,6 @@
+substitutions:
+  devicename: test1
+
 esphome:
   name: test1
   platform: ESP32
@@ -25,6 +28,10 @@ esphome:
           white: 100%
   build_path: build/test1
 
+packages:
+  wifi: !include test_packages/test_packages_package_wifi.yaml
+  pkg_test: !include test_packages/test_packages_package1.yaml
+
 wifi:
   networks:
   - ssid: 'MySSID'