GE Cloud integration, bug fixes

What's Changed

### Features

Givenergy Cloud is now integrated into Predbat, by setting ge_cloud_direct : True in apps.yaml you can directly control Givenergy inverters with the need for a seperate integration.

Note: This is not yet automatic, you will still need to configure apps.yaml to point to the entities created - in later versions an auto-config option will be available.

• Started GE Cloud integration by @springfall2008 in #1991
• Update apps-yaml.md by @springfall2008 in #2002

Bug fixes

• Freeze export was not working due to min improvement by @springfall2008 in #1998
• Rate overrides with date being ignored by @springfall2008 in #2000

Full Changelog: v8.14.4...v8.15.0