Add extra options for modifying upload rates to the webpack plugin

[Hamish-taylor]

This PR does the following:

• Adds a test project to the webpack plugin
• Adds extra options for controlling upload rates. This allows a user to increase delays if they are encountering rate limiting issues
• The plugin now only logs if all attempts have failed, this cleans up the log output. This also reduces confusion as it can appear that a file was not uploaded due to rate limiting even though it was successfully uploaded in a later attempt

[sumitramanga]

Just a couple of things otherwise, looks good!

[sumitramanga]

Amazing work, looks good! 🚀