Optimiser improvements, bug fixes

What's Changed

Features

Optimiser changes by @springfall2008 in #1838

• Restored the selection of charge SOC % on 30 minute charge slots
• Added new more aggressive logic to combine charge slots after optimisation, thus enabling low power mode without 'combine_charge' enabled.
• Adjusted weighting around freeze/charge/no-charge slightly

Octopus ready time sensor change by @springfall2008 in #1839

Supported the new select. octopus ready sensor

Bug fixes

Don't enable low power in monitor mode by @springfall2008 in #1841

Previous in monitor mode Predbat was predicting low power charging, which wasn't possible.

Bug in prediction not resetting charge rate by @springfall2008 in #1845

There was a bug where if the charge rate was set to 0 the plan produced was totally messed up.

Unit testing

Extra unit tests by @springfall2008 in #1842

Test updates by @springfall2008 in #1847

Full Changelog: v8.9.3...v8.10.0