Feature Request: Implement expiry feature for pastes (snippets)

[lnxpy]

A new field for Snippet model to set an expiration time. (e.g. one week, one month, one year,..)

• A management command that runs once every day and removes all the expired snippets.

[Farhaduneci]

Thank You Sadra! I will work on this one.

[Farhaduneci]

Pastes now support Expiry feature, the default value is set to One Day, so that pasteme-cli requires some updates too! I will open a PR on that soon.

@lnxpy Please check pasteme-cli repository for command line compability updates.

[lnxpy]

Thank you Farhad. :))