ROX-19589: Use a context with deadline for initialization.

[porridge]

Description

The primary motivation is to prevent fleetshard from getting stuck indefinitely on startup in case of transient network issues. ROX-19589 contains more background.

Note that the first time this change was merged (#1229) it caused the probe to break, even though e2e test passed. The cause is not well understood, but this time I took a detailed look into how the {{ctx}} passed into each New*Auth function is used. I found a single child call which saved it for subsequent use after the current function exits, so I passed a background context there.

Checklist (Definition of Done)

• Unit and integration tests added
• Added test description under Test manual
• Documentation added if necessary (i.e. changes to dev setup, test execution, ...)
• CI and all relevant tests are passing
• Add the ticket number to the PR title if available, i.e. ROX-12345: ...
• Discussed security and business related topics privately. Will move any security and business related topics that arise to private communication channel.
• Add secret to app-interface Vault or Secrets Manager if necessary
• RDS changes were e2e tested manually
• Check AWS limits are reasonable for changes provisioning new resources

Test manual

There isn't much we can test manually here outside of CI. This time we're better prepared for any unexpected side-effects:

• the change will first land into a new integration environment
• probes for different environments now use separate SSO orgs so different environments should not affect each other

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kovayur, porridge

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