Improve proxy URL regex matching

[zigzag1001]

Improve proxy URL regex matching

Description

Changes the URL matching regex to accept user:password proxies as well as normal public proxies.
Also generally improves proper url and ip format checking
regex101 demonstration: https://regex101.com/r/iS6jF6/108

Related Issue

Motivation and Context

I have a private proxy server that has a user:password requirement, without this change spotdl does not accept such proxies

How Has This Been Tested?

Tested by following poetry instructions in the project contribution guide and using a previously rejected proxy url.
Also tested on regex101 as linked to above.

Screenshots (if appropriate)

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• 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 read the CONTRIBUTING document
• I have read the CORE VALUES document
• I have added tests to cover my changes
• All new and existing tests passed