Move postgres credential info from fluentbit config to secrets

[niravparikh05]

Describe the issue you're facing

• Currently database credentials are part of fluentbit config map, these ideally should be part of secrets which fluentbit config can refer to.

[akshay196]

There is already paralus-db which holds db credentials. Need to see if fluentbit config can be referred to credentials from Secret. Otherwise some alternative to use credentials from.