bearer true

[johakoch]

• Add bearer = true for jwt block to indicate retrieving token from Authorization: Bearer ... (new default token source config).
• Deprecate use of header = "Authorization" for the same purpose.

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Reviewer checklist

• Read PR description: a summary about the changes is required
• Changelog updated
• Documentation: docs/{Reference, Cli, ...}, Docker and cli help/usage
• Pulled branch, manually tested
• Verified requirements are met
• Reviewed the code
• Reviewed the related tests