Fix container scanning parser

What does this MR do?

Follow up on Store container scanning results in the database this MR fixes few things:

• Add custom location object and use it to generate location_fingerprint
• Remove dead code (metadata_version method)
• Fix JSON indent (4 spaces => 2 spaces)

I highly recommend to use the Hide whitespace changes option to better visualize the diff.

What are the relevant issue numbers?

#9090 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• EE specific content should be in the top level /ee folder
• For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?
• Security reports checked/validated by reviewer

Closes #9090 (closed)