Bug fixes: AC Coupled model, HTML plan, Solis charging

What's Changed

Bug fixes

Inverter service calls were made before updating start/end times:

• Potential fix for not hold charging with Solis by @springfall2008 in #1701

HTML Plan sometimes did not show export slots:

• Bug in HTML report row span, change to model related to metric keep a… by @springfall2008 in #1706

Bug in AC Coupled model leading to export slots being put too early in the day

• Fix bug related to export slot timing on AC Coupled mode by @springfall2008 in #1707

Better way to debug plans

When 'debug_enable' is on Predbat now writes out complete model state into the 'debug' directory. This can be used by the unit test code to reproduce the generated plan and debug the optimiser/model.

• Method to save/restore state of Predbat instance by @springfall2008 in #1702
• Debugging via saved yaml by @springfall2008 in #1705

Full Changelog: v8.8.2...v8.8.3