Add OIDC Configuration

[JasonPowr]

This pr allows for the configuration of an OIDC provider with the tas installer

Installs Trusted Artifact Signer (TAS) on a Kubernetes cluster.

        This command performs a series of actions:
        1. Initializes the Kubernetes client to interact with your cluster
        2. Sets up necessary certificates
        3. Configures secrets
        4. Deploys TAS to openshift

Usage:
  tas-installer install [flags]

Flags:
      --chartVersion string      Version of the Helm chart (default "0.1.26")
  -h, --help                     help for install
      --oidc-client-id string    Specify the OIDC client ID
      --oidc-issuer-url string   Specify the OIDC issuer URL e.g for keycloak: https://[keycloak-domain]/auth/realms/[realm-name]
      --oidc-type string         Specify the OIDC type
      --valuesFile string        Custom values file for chart configuration

Global Flags:
      --kubeconfig string   Specify the kubeconfig path (default "/home/japower/.kube/config")

It adds three new flags to the installer --oidc-client-id, --oidc-issuer-url and --oidc-type

[JasonPowr]

The ioutil.TempFile() is deprecated, so I swapped it out for os.CreateTemp()

[JasonPowr]

Also changed this to the local chart, as the oci one does not have a 0.1.26 tag

[sallyom]

oh great! and I have a PR to make the chartURL configureable, so I'll pull in this change - this filesystem url will be the default until we have a stable OCI chart

[sallyom]

Nice! I have a follow-up for the chartURL - we might rename it from chartURL to chartSomethingElse since with the local chart path it's not technically a URL - I'll add this to PR #127 though and let's merge this as/is!