Refactor code

Problem/Motivation

The code is repetitive and unnecessarily complex. There's also many PHP CodeSniffer issues that need to be resolved.

Remaining tasks

• Move the method from the HttpDownloadLinkLabeler class to the FilterDownloadLinkLabeler class.
• Refactor FilterDownloadLinkLabeler to use new method to get remote file size.
• Delete the HttpDownloadLinkLabeler class and the HttpDownloadLinkLabelerTest class.
• Run PHP CodeSniffer and remediate issues.
• Refactor FilterDownloadLinkLabeler class to reduce complexity.
• Convert public properties to private that are only needed to be used in class.