doc: add retrieve access key document

[AlphaWong]

related to #385

[alalamav]

Thank you for the contibution, @AlphaWong.

The access key directory is used on legacy Outline servers, the new location for the access key config on the container is: /root/shadowbox/persisted-state/shadowbox_config.json. Similarly, the Outline server configuration is at: /root/shadowbox/persisted-state/shadowbox_server_config.json.

[AlphaWong]

Thank you for the contibution, @AlphaWong.

The access key directory is used on legacy Outline servers, the new location for the access key config on the container is: /root/shadowbox/persisted-state/shadowbox_config.json. Similarly, the Outline server configuration is at: /root/shadowbox/persisted-state/shadowbox_server_config.json.

So, should I modify the document?

[alalamav]

So, should I modify the document?

That would be great. Thanks!

[AlphaWong]

So, should I modify the document?

That would be great. Thanks!

updated. plz take a look