Revision 14

[jakobilobi]

Charm updates to be included in Revision 14.

• Updated binary-sha256-url description
• Add actions to stop and to start the polkadot service
• Some readme updates and restructuring
• Upgrade ops version to 2.9
  • v2.8 comes with a Unit.reboot() implementation and v2.9 has support for Python 3.12 :tada:
• Change operator framework imports to 'import ops' style
• Update how update_status sets its status
• Rename start_polkadot to start_service (also for stop, restart)
• Add action to get output from './polkadot --help'

[jakobilobi]

Various updates for the Polkadot charm - please review and comment!

Anything more that you want in the next revision? Speak up!