feat(OAuth2): Migrated OAuth2 configuration to align with Spring Security 5 Java DSL standards

[rahul-chekuri]

• Replaced the legacy security.authn.oauth2 structure with the new spring.security.oauth2.client configuration.
• Updated property mappings to conform to Spring Security 5's expectations.
• Ensured compatibility with existing hal config security authn oauth2 edit commands.

Old Configuration that used get populated gate.yml:

security:
  authn:
    oauth2:
      enabled: true
      client:
        clientId: <client-id>
        clientSecret: <client-secret>
        accessTokenUri: https://www.googleapis.com/oauth2/v4/token
        userAuthorizationUri: https://accounts.google.com/o/oauth2/v2/auth
        scope: profile email
      userInfoRequirements:
        hd: <domain>
      resource:
        userInfoUri: https://www.googleapis.com/oauth2/v3/userinfo
      userInfoMapping:
        email: email
        firstName: given_name
        lastName: family_name
      provider: GOOGLE

New Configuration that gets populated in gate.yml (Aligned with Spring Security 5):

spring:
  security:
    oauth2:
      client:
        registration:
          google:
            client-id: <client-id>
            client-secret: <client-secret>
            scope: profile,email
        provider:
          google:
            authorization-uri: https://accounts.google.com/o/oauth2/auth
            token-uri: https://oauth2.googleapis.com/token
            user-info-uri: https://www.googleapis.com/oauth2/v3/userinfo

Commands remain unchanged:

hal config security authn oauth2 edit --provider google --client-id some_id --client-secret some_secret --user-info-requirements hd=company.io

[spinnakerbot]

The following commits need their title changed:

• b62f2c2: Add new GateBoot667ProfileFactory that emits the new gate config.

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