Added validation function to validate Update Profile request body

[isabelcosta]

Description

• Added a validation function to validate request data sent for PUT /user API.
• Added a lot of tests for each new function added.
• Added new utils functions to avoid mistakes in the future regarding the string used for length validation errors
• Added utils to strip strings before checking their length
• Allow usernames to contain "_"

Fixes #96
Fixes #97

Type of Change:

• Code

Code/Quality Assurance Only

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Created a lot of tests for validation functions and api, and did a quick test on Swagger UI

Checklist:

• My PR follows the style guidelines of this project
• I have performed a self-review of my own code or materials

Code/Quality Assurance Only

• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes