Allow `getKeys` to optionally skip errors

[ManUtopiK]

Describe the feature

When mounting multiple storage, if one of the mountpoint throw an error, it breaks all. Let's say I mount a fs storage and http storage. If http is down, I can't get only the fs storage. storage.getKeys() throw an error. How to prevent this and obtain the fs storage anyway?

Additional information

• [ ] Would you be willing to help implement this feature?

[ManUtopiK]

In fact, if the driver doesn't throw an error, calling storage.getKeys() return well the others mounted storages. I tried to comment the error here for the gitlab driver and it works. Should we throw an error ?