Add the external module for SAML SSO

[antepusic]

Description

This PR adds an external module that enables SAML single sign-on by validating SAML responses. The supported identity providers are Microsoft Entra ID and Okta.

NB: Auth stack extensions have been made in #1990.

[master < Task] PR

• Write E2E tests
• Provide the full content or a guide for the final git message
  • [FINAL GIT MESSAGE]

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Documentation checklist

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• Write a release note, including added/changed clauses
  • [Release note text]
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[imilinovic]

Looks good now but I am not 100% familiar with saml standards.

[gitbuda]

Add requirements.txt under src/auth/reference_modules/ + install it during memgraph install, update documentation, how users should install all deps required to run reference modules.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud