asset-syncer sync job exposes AuthorizationHeader basic auth in logs

[RGPosadas]

Describe the bug

If an AppreRepository is configured with basic auth, then asset-syncer will log out the AuthorizationHeader. The log will include basic auth key/value pair (base64 encoded).

To Reproduce
Steps to reproduce the behavior:

1. Configure an AppRepository with Basic Auth
2. Sync the AppRepository
3. Investigate the sync container logs, you will get:

I0520 21:03:20.555658       1 root.go:32] asset-syncer has been configured with: server.Config{DatabaseURL:"apps-postgresql:5432", DatabaseName:"assets", DatabaseUser:"postgres", DatabasePassword:"REDACTED", Debug:false, Namespace:"ns", OciRepositories:[]string{"my-chart"}, TlsInsecureSkipVerify:false, FilterRules:"", PassCredentials:false, UserAgent:"asset-syncer/2.8.0 (kubeapps/2.10.0)", UserAgentComment:"kubeapps/2.10.0", GlobalPackagingNamespace:"kubeapps", KubeappsNamespace:"", AuthorizationHeader:"Basic <EXPOSED AUTH>", DockerConfigJson:""}

Expected behavior
A clear and concise description of what you expected to happen.

Similarly to Config.DatabasePassword, the AuthorizationHeader is redacted.

Desktop (please complete the following information):

• Version 2.10.0