Add to List Users API the ability to filter users by skills

## Description
As a member of the app,
I need be able to filter other members by their skills,
so that I can choose the member I want to create a mentorship relation with.

APIs used to fetch Users, don't have an option to filter users by `skills` attribute.

#### Note: This issue is labeled for Open Source Hack.
I can assign this issue to you on September 1st as the official opening date for Open Source Hack. Please free to check out other issues in the meantime. Program website: https://anitab-org.github.io/events/open-source-hack/

## Acceptance Criteria
### Update [Required]
- [ ] Add a query parameter support to `GET /users` and `GET /users/verified`, to filter users by `skills` attribute.
- [ ] Update Swagger UI documentation for this API.
- [ ] Write at least one test to prove your new feature is working.

## Definition of Done
- [ ] All of the required items are completed.
- [ ] Approval by 1 mentor.

## Estimation
[4] hours