Fix issue with gap filling and correct end_record calculation

What's Changed

• Improvements and fixes by @springfall2008 in #471
• Fix typo by @springfall2008 in #472
• Calculate end_record more correctly based on real charging not extra slots by @springfall2008 in #474
• Sofar inverter fix by @springfall2008 in #477
• Load filter - make the gap size configurable in apps.yaml by @springfall2008 in #478
• Fix reserve modelling bug with discharge by @springfall2008 in #479

Full Changelog: v7.14.12...v7.14.13