[Package]: Create platform e2e testing package

[carcruz]

[Package]: Create platform e2e testing package

Issue: opentargets/issues#3374

Description

As OT Maintainers, we want to automate part of the release validations using a platform-specific test suite.
This is an initial implementation of a new package (platform-test) that uses the Playwright framework to carry a list of page-specific UI validations.

Todo:

• Scripts documentation
• URLs define by env variables
• GH action to trigger test on PR || Tag
• Define first-iteration test suit

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Test itself 🥇
• Run test commands locally

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules