GH-3258: Support for bzip2 encoding in HTTP uploads.

[Aklakan]

GitHub issue resolved #3258

• Draft because so far this PR only addresses uploading a remote file via HTTP.
• I still need to investigate whether upload of a local bz2 file in fuseki needs extra work.

Pull request Description: Proposal to adds bzip2 as a recognized encoding to HttpLib.

Note: The Web server from which one attempts to upload a file needs to be configured to serve content type and encoding separately:

curl -I http://myserver/file.nt.bz2

Content-Type: application/n-triples
Content-Encoding: bzip2

For example, by default, the Apache Web server would serve .bz2 files as Content-Type: application/x-bzip2. This way a client wouldn't know what actual content is being encoded.

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• Tests are included.
• Documentation change and updates are provided for the Apache Jena website
• Commits have been squashed to remove intermediate development commit messages.
• Key commit messages start with the issue number (GH-xxxx)

By submitting this pull request, I acknowledge that I am making a contribution to the Apache Software Foundation under the terms and conditions of the Contributor's Agreement.

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See the Apache Jena "Contributing" guide.