SQL views guidance

[alexsnowdon]

Merge request template: please remove the appropriate parts of this template.

Pre-merge request checklist (to be completed by the one making the request):

• [x] I have performed a full review of this code myself.
  • For Python code in PySpark specific sections, all code should have been run in Jupyter notebooks.
  • For code in sections of the book containing both Python and R code, the page of the book should be constructed as described in the contributing guide and converted to a markdown file.
• [x] editing the code was not required here but I did check the code fits with the formatting in the rest of the book
• [x] I have built the book as outlined in the contributing guide and confirmed that any additional/modified content is displaying as expected. Unable to build due to blockers on computer.

Details of this request (such as):

• I have added a new page into the Ancillary section of the book called 'Creating SQL views in HDFS'
• I have added two new images to the 'images' folder that are referenced in the new page
• The page is based on the guidance on our Gitlab under how-to/SQL views. I have edited the wording and added new sections to give more information on SQL views.

Requirements for review (such as):

• Read the content to make sure you it makes sense and covers the important bits.
• Check the code runs (none of the code has been edited).
• Make sure the images show correctly (x2).
• Please build the book and make sure the .html shows correctly (I have been unable to test this).

[Jday7879]

Book built correctly locally, but has not loaded images on the deployed version

[alexsnowdon]

new branch created called png which has the changes for the image issue mentioned above for the deployed page version