Covalent-ssh-plugin

Changed

- Changed the readme banner

Changed

- Switched to asynchronous SSH connections making the executor async-aware.
- Tests have been updated to reflect the switch to async ssh connections.

Changed

- New logo to reflect revamp in UI.
- Backport some changes

Fixed

- Handle exceptions correctly.
- Fix return type when ssh connection fails.
- Fix tests

Added

- Unit tests written and added to the .github workflows.

Changed

- Small refactor to align with the Covalent micro-services refactor.

Changed

- Changed global variable executor_plugin_name -> EXECUTOR_PLUGIN_NAME in executors to conform with PEP8.