c8y-configuration-plugin to detect local updates to its config file / Focus on our inotify library

[albinsuresh]

When the c8y-configuration-plugin.toml file is updated locally from the device, the plugin doesn't reload its contents as done by the c8y-log-plugin. The same file watcher mechanism implemented for c8y-log-plugin must be implemented for the c8y-configuration-plugin as well. Whenever the config file is updated, either locally or via cloud, the updated list of config types must be sent to Cumulocity via the SmartREST 119 message.

[rina23q]

Don't do only copy-and-paste. The code where will be duplicate must be addressed as library so that we can avoid code duplication.

[rina23q]

We decided to split down this issue.

• This issue focuses only on creating our fs_inotify library.
• Applying the crate to each components will be addressed in #1246, #1247, and #1248.