Filesystem monitoring using notify-rs

[kirillt]

Can we benefit from this crate?
https://github.com/notify-rs/notify

[tareknaser]

To recap our discussion:
We've decided to add a method in arklib called ResourceIndex::watch_index() to monitor a specific directory for changes and update the index whenever a change is detected.
For interacting with this method, we'll add a command to ark-cli which is ark-cli watch <path>

To further build on this, we plan to enhance this functionality to enable watching multiple directories simultaneously. This will be possible through the following commands:

• ark-cli watch --all to watch all specified directories.
• ark-cli watch pin <path> to add a directory to the watch list.
• ark-cli watch unpin <path> to stop watching a directory.
• ark-cli watch list to list the directories currently being watched.

We can also have a global configuration file, such as /Users/<username>/.ark/directories_to_watch, to store the list of directories to monitor.

[tareknaser]

We can close this issue in favor of ARK-Builders/ark-core#21