Add SSH config options to template

[avo-sepp]

Added 3 optional values to chart

• policyRepoSshKey
• policyRepoClonePath
• policyRepoMainBranch

Which respectivly map to the following ENV

• OPAL_POLICY_REPO_SSH_KEY
• OPAL_POLICY_REPO_CLONE_PATH

• OPAL_POLICY_REPO_MAIN_BRANCH

  Repo SSH Key is stored as a Kubernetes Secret

[RazcoDev]

LGTM :)