Remove robustness presubmits and periodics workflows

This commit will remove robustness presubmits
for both `amd64` and `arm64` archs, periodics for
`amd64` arch since it has been migrated to test-infra
as prowjobs:
https://github.com/kubernetes/test-infra/blob/master/config/jobs/etcd/etcd-periodics.yaml#L61-L230
https://github.com/kubernetes/test-infra/blob/master/config/jobs/etcd/etcd-presubmits.yaml#L240-L279

Signed-off-by: ArkaSaha30 <arkasaha30@gmail.com>

.github/workflows/robustness-nightly.yaml

@@ -11,17 +11,6 @@ on:
   workflow_dispatch:
 
 jobs:
-  main:
-    # GHA has a maximum amount of 6h execution time, we try to get done within 3h
-    uses: ./.github/workflows/robustness-template.yaml
-    with:
-      etcdBranch: main
-      count: 150
-      testTimeout: 200m
-      artifactName: main
-      runs-on: "['ubuntu-latest-8-cores']"
-      scenario: TestRobustnessExploratory
-      lazyfsEnabled: true
   main-arm64:
     uses: ./.github/workflows/robustness-template.yaml
     with:
@@ -32,16 +21,6 @@ jobs:
       runs-on: "['actuated-arm64-12cpu-8gb']"
       scenario: TestRobustnessExploratory
       lazyfsEnabled: false
-  release-35:
-    uses: ./.github/workflows/robustness-template.yaml
-    with:
-      etcdBranch: release-3.5
-      count: 150
-      testTimeout: 200m
-      artifactName: release-35
-      runs-on: "['ubuntu-latest-8-cores']"
-      scenario: TestRobustnessExploratory
-      lazyfsEnabled: true
   release-35-arm64:
     uses: ./.github/workflows/robustness-template.yaml
     with:
@@ -52,13 +31,3 @@ jobs:
       runs-on: "['actuated-arm64-12cpu-8gb']"
       scenario: TestRobustnessExploratory
       lazyfsEnabled: false
-  release-34:
-    uses: ./.github/workflows/robustness-template.yaml
-    with:
-      etcdBranch: release-3.4
-      count: 150
-      testTimeout: 200m
-      artifactName: release-34
-      runs-on: "['ubuntu-latest-8-cores']"
-      scenario: TestRobustnessExploratory
-      lazyfsEnabled: true

.github/workflows/robustness.yaml

@@ -1,25 +0,0 @@
----
-name: Robustness
-on: [push, pull_request]
-permissions: read-all
-jobs:
-  main:
-    uses: ./.github/workflows/robustness-template.yaml
-    with:
-      etcdBranch: main
-      count: 12
-      testTimeout: 30m
-      artifactName: main
-      runs-on: "['ubuntu-latest-8-cores']"
-      scenario: TestRobustness
-      lazyfsEnabled: true
-  main-arm64:
-    uses: ./.github/workflows/robustness-template.yaml
-    with:
-      etcdBranch: main
-      count: 12
-      testTimeout: 30m
-      artifactName: main-arm64
-      runs-on: "['actuated-arm64-12cpu-8gb']"
-      scenario: TestRobustness
-      lazyfsEnabled: false