Add support for mTLS

[bputt-e]

Overview

Add CA_CERT TLS_KEY TLS_CERT to provider to enable support for mTLS

Possible Implementation

Similar to https://registry.terraform.io/providers/elastic/elasticstack/latest/docs where that provider allows setting ca_file, cert_file, key_file when communicating with elasticsearch

Testing

Add nginx in front of ECE with mTLS requirement to validate the ca_file, cert_file, key_file works as expected

Context

We are trying to enforce mTLS...While we can configure nginx to remove validation of the cert, it'd be ideal if we can keep it consistent.

Your Environment

Nginx sits in front of ECE and therefore handles TLS termination among other features.