Bug fixes, rH sensors, improved example dashboard

👉 Changes to the integration itself:

• fixed wrong temperature balance calculation (switched sides in subtraction),
• fixed wrong efficiency value at equal temperatures (0→100),
• fixed boost mode not starting again if cancelled before,
• preparations for future config flow + options flow setup,
• reworked major parts of the Wiki (especially installation guides),
• added rH sensors (both raw and real values - thanks to @ragg987),

👉 Changes to the example dashboard:

• Please go through the dashboard installation guide again to update your YAML.
• complete rework of the dashboard,
• improved displaying on smartphones,
• merged the two separated 'remote controls' into one,
• remote control now auto-detects browser language (en, de, nl, dk, sk, no, fi),
• plots are now linked (all 3 are zooming / scrolling together),
• new temperature balance display.

👉 Internal changes:

• added Github action and settings to protect the :main branch from PR's,
• added new input_number ventilation_display_select for new remote control buttons,
• re-arranged / cleaned Github file structure,
• moved old, unused files to zz_old_or_deprecated.