Improve readiness diagnotics messages

[errordeveloper]

Before:

Plan: 0 to add, 1 to change, 0 to destroy.
╷
│ Warning: Flux controllers are not healthy and will be redeployed
│ 
│   with module.user_flux.flux_bootstrap_git.flux,
│   on ../../../common/flux/main.tf line 15, in resource "flux_bootstrap_git" "flux":
│   15: resource "flux_bootstrap_git" "flux" {
│ 
│ failed to configure authentication options: invalid 'ssh' auth option: 'identity' is required

After:

╷
│ Warning: Flux resources GitRepository and Kustomization in flux-system namespace are not ready and Flux will be redeployed
│ 
│   with module.user_flux.flux_bootstrap_git.flux,
│   on ../../../common/flux/main.tf line 15, in resource "flux_bootstrap_git" "flux":
│   15: resource "flux_bootstrap_git" "flux" {
│ 
│ GitRepository/flux-system: failed to configure authentication options: invalid 'ssh' auth option: 'identity' is required
╵

[stefanprodan]

LGTM

Thanks @errordeveloper 🏅

[swade1987]

Nice work @errordeveloper 💪