Issue #3034595 by mlargo2: Support multiple arguments with spaces on views contextual filters
Closes #3034595. Views contextual filters with multiple values do not work with arguments containing spaces, so the changes to solve it were:
- The option "preserve_spaces" was added to contextual filters form
- The logical to detect and process AND(,) and OR(+) operations if multiple_values option is checked, was improved.
- Testing code was added to check the new option.