Change default delegate sorting to rank:asc - Closes #2138

[Tschakki]

What was the problem?

Default sorting for the list of delegates in Lisk Core API was rank:desc

How did I fix it?

Changed it to rank:asc, as this is the behaviour which is expected as default.

How to test it?

Make GET /api/delegates request without specifying the sort parameter.
Response should be sorted by rank in ascending order.

Review checklist

• The PR solves Delegates endpoint should sort by rank:asc #2138
• All new code is covered with unit tests
• All new code was formatted with Prettier
• Linting passes
• Tests pass
• Commit messages follow the commit guidelines
• Documentation has been added/updated

[nazarhussain]

I am good with change. Only concern is this may break any third party tool which is relaying on default sorting of this endpoint. Should we include it in minor release? @MaciejBaj

[MaciejBaj]

Changing a default parameter doesn't break the API in my opinion. We can proceed with this PR.