New features and optimisation improvements

What's Changed

• Iboost - added gas and battery charging options by @springfall2008 in #520
• Add iboost balancing payment logic by @springfall2008 in #521

From v7.14.20 Beta:

• improve handling of discharge on charge by @springfall2008 in #515
• Reset inverter settings when certain options are changed by @springfall2008 in #517
• Update customisation.md by @springfall2008 in #518
• Tweaks to inverter reset to avoids resets in read-only mode by @springfall2008 in #519

Full Changelog: v7.14.20...v7.14.21