Deprecate/Archive lbrlabs providers

[iwahbe]

The upstream maintainer has indicated that he is not interested in maintaining these packages. Since they may still be in use, we should not remove them from the registry. We should mark them as deprecated so users understand that they are no longer supported.

We should deprecate:

• lbrlabs/pulumi-iosxe
• lbrlabs/pulumi-nxos
• lbrlabs/pulumi-awscontroltower

We should archive (mirroring upstream):

• lbrlabs/pulumi-launchdarkly
• lbrlabs/pulumi-vantage