Rename uploading files

[hacksparrow]

Description

This PR adds the feature to rename files before they reach the destination - filesystem or cloud.

I have made additional changes to the test cases and edited the .gitignore file under /test/images/album1. Reason: each unit test should be self-contained.

NOTE: This feature depends on an update in strong-remoting. CI will fail till strong-remoting is updated (it is not updated yet).

Related issues

• connect to https://github.com/strongloop/loopback-component-storage/issues/240

Checklist

• [x] New tests added or existing tests modified to cover all changes
• [x] Code conforms with the style guide

[hacksparrow]

Closing this in favor of documenting the getFilename datasource option, which can be used for accomplishing the requirement.