Fixed certificate is ignored when using own secret

[hvaghani221]

Added following config when using self-created secrets.
Fixes #805

# Create or use existing secret if the name is empty default name is used
secret:
  create: true
  name:
  # Ignore follwoing config if create is false 
  # Enable it if secret has hec_client_key
  has_client_key: false
  # Enable it if secret has hec_client_cert
  has_client_cert: false
  # Enable it if secret has hec_ca_file
  has_ca_file: false

Enable the required config according to the keys available in the self-created certificates.