feat(keycloak): add parameter clockSkew to jwtBearerOptions

[ntruchsess]

Description

Parameter validateLifetime has been added to the configuration of backendservices to enable expiration-check of keycloak-tokens.

Why

without this configuration the backendservices accept expired tokens from keycloak. This is a security-issue.

Issue

https://github.com/eclipse-tractusx/portal-backend/issues/586

Link to pull request from other repository. N/A

Checklist

Please delete options that are not relevant.

• [X] I have performed a self-review of my changes