add templates for central monitoring

[msherman64]

This takes our current, ad-hoc configuration for sending metrics+logs to our central infra, and finally merges it into chi-in-a-box.

Two new toggles are added, defaulting to false, upload_logs_chameleon and upload_metrics_chameleon.
The fluentd and prometheus template files are only populated if these are true, preventing the current behavior from changing.

This also assumes that keystone_idp_client_id is used as the username for each site for pushing to both loki and mimir, and that the prometheus_remote_write_password is used as the password for both.

[msherman64]

Of note, any sites that already have these files in their site config will:

• (if the names match) override this config
• (if the names don't match) probably duplicate the config, but not unless the "upload_" toggles are turned on

the migration path is to just remove the overrides from site config once these is merged and enabled