fix: remove old operator-sdk

[Elyytscha]

What type of PR is this?

/kind bug

What does this PR do / why we need it:

This PR removes the old operator-sdk dependency

Have you updated the necessary documentation?

I think we need no doc update for this

Which issue(s) this PR fixes:

Fixes #461

How to test changes / Special notes to the reviewer:

build and deploy operator

apply some argocd:

apiVersion: argoproj.io/v1beta1
kind: ArgoCD
metadata:
  name: gitops-test
spec:
  server:
    autoscale:
      enabled: false
    grpc:
      ingress:
        enabled: false
    host: gitops-test.domain.com
    ingress:
      enabled: false
    resources:
      limits:
        cpu: '1'
        memory: 2Gi
    route:
      enabled: true
      tls:
        insecureEdgeTerminationPolicy: Redirect
        termination: Passthrough
    service:
      type: ''
  grafana:
    enabled: false
    ingress:
      enabled: false
    route:
      enabled: false
  monitoring:
    enabled: true
  notifications:
    enabled: true
  prometheus:
    enabled: false
    ingress:
      enabled: false
    route:
      enabled: false
  initialSSHKnownHosts: {}
  banner:
    content: Magische Devopsmagie
    url: 'https://console.apps.domain.com'
  sso:
    dex:
      openShiftOAuth: true
    provider: dex
  statusBadgeEnabled: true
  rbac:
    defaultPolicy: 'role:readonly'
    policy: |
      g, okd-cluster-admin, role:admin
    scopes: '[groups]'
  extraConfig:
    resource.customizations: |
      operators.coreos.com/Subscription:
        health.lua: |
          hs = {}
          hs.status = "Progressing"
          hs.message = ""
          if obj.status ~= nil then
            if obj.status.state ~= nil then
              if obj.status.state == "AtLatestKnown" then
                hs.message = obj.status.state .. " - " .. obj.status.currentCSV
                hs.status = "Healthy"
              end
            end
          end
          return hs
  repo:
    extraRepoCommandArgs:
      - '--max-combined-directory-manifests-size'
      - 25M
    replicas: 2
  ha:
    enabled: false
  tls:
    ca: {}
  redis: {}
  controller:
    processors: {}
    sharding: {}

[saumeya]

Hi @Elyytscha , thanks a lot for this PR. I have gone through it and looks good.

There were some additional changes that I found while going through the upgrade documentation and I have added those and made a draft PR - https://github.com/argoproj-labs/argocd-operator/pull/1447/files

Let me know if you want to collaborate, or close this in favor of that.
I also have to check the migration steps involved for kubebuilder v3 -> v4 and if our project needs it, will update regarding that next week.