Add support for random ordering with seeds

[asharirfan]

Description of the Change

This PR adds support for using RAND function in the orderby field for search queries.

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Applicable Issues

#1490

Changelog Entry

• Add support for RAND function for orderby field in search queries.

[tlovett1]

Looks like this is already supported. What does this PR do?

[asharirfan]

Looks like this is already supported. What does this PR do?

@tlovett1 Right now, only 'orderby' => 'rand' is supported. This PR adds the support for the RAND function which lets a user pass seed value to the function.

You can read more about it over here: #1490 (comment)

[mustafauysal]

@brandwaffle I have added the test in f70ee87
Can we do cherry-pick after the merge this PR?