Allow more options to be configured from repo options file.

[gudmdharalds]

See background in #141.

TODO:

• Implement options found in list of booleans in Allow configuration of more parameters via repository options file #141 (first list)
• Add new options to --repo-options-allowed
• Test new options via repo configuration file
  • Test results-comments-sort
  • Test review-comments-include-severity
  • Test phpcs
  • Test hashes-api
  • Test svg-checks
  • Test autoapprove
  • Test autoapprove-php-nonfunctional-changes
• Update README
  • Move documenttion of options under heading "Configuration via repository config-file" to the feature documentation itself as possible
  • Document new config-file options:
    • results-comments-sort
    • review-comments-include-severity
    • phpcs
    • hashes-api
    • svg-checks
    • autoapprove
    • autoapprove-php-nonfunctional-changes
• Run full-unit tests
• Check automated unit-tests

Note: No need for updated unit-tests.