Remove RDD suffixes on file, class, and object names.

[ruebot]

GitHub issue(s): #468

What does this Pull Request do?

Remove RDD suffixes on file, class, and object names.

• Remove all the RDD suffixes added previously
• Rename image_graph to imagegraph (Python)
• Rename GetExtensionMime to GetExtensionMIME (Scala)
• Remove textFiles (Scala)
• Remove text_files (Python)
• Remove TextFilesInformationExtractor
• Rename files all affected files as needed
• Update tests as needed

How should this be tested?

• TravisCI should do it
• But, a good sniff test would be good as well.

Additional Notes:

• Since there is so much documentation changes, I'll get the documentation updated on the docusaurus updates I'm working on. I'll try and push up a branch there with the changes today.
• Notebooks will need to be updated. I'll try and get that updated later today as well

[ruebot]

Documentation updates are over here. They'll get in the website when the time comes.

[codecov[bot]]

Codecov Report

Merging #479 into master will decrease coverage by 0.19%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #479      +/-   ##
==========================================
- Coverage   83.88%   83.69%   -0.20%     
==========================================
  Files          44       43       -1     
  Lines        1297     1245      -52     
  Branches      250      239      -11     
==========================================
- Hits         1088     1042      -46     
  Misses         80       80              
+ Partials      129      123       -6