bootstrapping: added validation case for repo url without scheme

[enekofb]

Part of #3659

What changed?

• Handled validation case where repo URL does not have scheme
• Refactored git repo configuration

Why was this change made?

• We currently do not support git repo URLs without scheme but the validation of the repo configuration didn't support it so translated into a internal error instead of user input. this PR changes this.

How was this change implemented?

How did you validate the change?

• Explain how a reviewer can verify the change themselves

Run bootstrapping with a repo URL without scheme ... you should see an error

➜  weave-gitops-enterprise git:(wge-3659-validation-ssh) ✗ go run cmd/gitops/main.go bootstrap \                                         <aws:sts>
     --private-key=abc  --private-key-password="" \
     --version="0.36.0" \
     --domain-type="localhost" \
     --password="admin123"  \
     --branch="main"  \
     --repo-path=clusters/management


► creating client to cluster
✔ created client to cluster: https://127.0.0.1:63867
◎ checking flux
► verifying flux installation
✗ flux installed error: ► checking prerequisites
✔ Kubernetes 1.27.3 >=1.25.0-0
► checking controllers
✗ no controllers found in the 'flux-system' namespace with the label selector 'app.kubernetes.io/part-of=flux'
► checking crds
✗ no crds found with the label selector 'app.kubernetes.io/part-of=flux'
✗ check failed
. flux is not bootstrapped in 'flux-system' namespace: more info https://fluxcd.io/flux/installation
◎ bootstrap flux
? do you want to bootstrap flux using the generic way? [y/N] y█
◎ flux repository configuration
please enter your flux git https or ssh repository url: [email protected]/enekofb/cli-dev
Error: cannot execute bootstrap: cannot execute 'flux repository configuration': error creating git repository configuration: error parsing repo scheme: repository scheme cannot be empty
exit status 1

• Unit tests -- what is covered, what cannot be covered; are
  there tests that fail without the change?

Added validation test case for the empty scheme scenario

Release notes

Documentation Changes

Other follow ups

[waleedhammam]

LGTM