docs(setup): 📝 update install instructions using hatch v1.8

[Olaf-Wolf3D]

Description

Since hatch v1.8, no additional env manager, like conda/mamba, is needed anymore.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• 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 not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Tested locally on Windows 11

Test Configuration:

• Did you use the test environment provided by the project (e.g. a hatch action)?
  Yes, tested creation of hatch default env, and running tests using hatch run test

Checklist

• I confirm that the changes meet the user experience and goals outlined in the design plan (if there is one).
• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have updated any version info, if necessary.
• 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

Task: TECHART-353