OLS-2604 add google vertex provider

[raptorsun]

Description

This PR adds Google Vertex AI as a provider.
It has 2 types google_vertex and google_vertex_anthropic, for generic model and Claude models respectively.
This only works in combination of the service PR openshift/lightspeed-service#2877

Type of change

• Refactor
• New feature
• Bug fix
• CVE fix
• Optimization
• Documentation Update
• Configuration Update
• Bump-up dependent library

Related Tickets & Documents

• Related Issue #
• Closes # OLS-2604

Checklist before requesting a review

• I have performed a self-review of my code.
• PR has passed all pre-merge test jobs.
• If it is a core feature, I have added thorough tests.

Testing

• Please provide detailed steps to perform tests related to this code change.
• How were the fix/results from this change verified? Please provide relevant screenshots or results.

[openshift-ci]

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[openshift-ci]

@raptorsun: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/bundle-e2e-4-21	3c1635a	link	true	/test bundle-e2e-4-21

Full PR test history. Your PR dashboard.

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