Calculate cost savings, bug fixes

What's Changed

Predbat can now calculate your cost savings vs not using Predbat (approximate) and vs not having Solar/Battery system.

• Calculate cost savings by @springfall2008 in #1083
  • Enable calculate savings by default, change clock skew reset threshold to 10 minutes by @springfall2008 in
  • Baseline cost savings against charging at lowest rate only by @springfall2008 in #1089
  • Update index.md by @springfall2008 in #1099

There is a new chart (template in the templates area at the end of example charts)

And also new entities to track the total cost saving over time 'predbat.savings_total_predbat and 'predbat.savings_total_pvbat

Lots of bug fixes:

• Fix issue with pause charge remaining on during Charge by @springfall2008 in #1086
• Fix bug in in-day adjustment with PredAI by @springfall2008 in #1090
• Fix: parameter formatting error for get_history by @ncains in #1088
• Fix crash when calculate savings is enabled by @springfall2008 in #1091
  #1092
• Fix typo's causing crashes by @springfall2008 in #1093
• Fixes to ensure previous days rates track also by @springfall2008 in #1094
• Potential fix to freeze issue by @springfall2008 in #1095
• Fix typo, update to .19 by @springfall2008 in #1096
• Another attempt to fix docker version by @springfall2008 in #1097
• Fix for car charging rounding issue by @springfall2008 in #1098

New Contributors

• @ncains made their first contribution in #1088

Full Changelog: v7.18.6...v7.19.0