imagePullSecrets missing in the helm chart values of monocular

[abdennour]

Usually, in offline/disconnected environments, container images are fetched from private registries.
To do that, we assign imagePullSecrets.
However, the helm chart of monocular does not provide a way to specify imagePullSecrets.

Please accept my PR if i fixed. Or fix it kindly

[abdennour]

i am feeling that this repo is out of support. i hope i am mistaken