Add to chat the ability to mount client certificates for admin tools deployment

[AnjeiKozhev]

Is your feature request related to a problem? Please describe.

My cluster is deployed using chart version 1.22.1. After enabling full mTLS, I am not able to use the tstl utility, which requires a client certificate. In the current admintools-deployment.yaml template, I do not see the ability to add and mount a volume containing the necessary certificates from the Kubernetes secret.

Describe the solution you'd like

add such an opportunity to the chart or add a description to the readme if such an opportunity already exists.

Additional context

[robholland]

Implemented in #463