reinitialize-pods controller

Fixes linkerd/linkerd2#11073

This fixes the issue of injected pods that cannot acquire proper network
config because `linkerd-cni` and/or the cluster's network CNI haven't
fully started. They are left in a permanent crash loop and once CNI is
ready, they need to be restarted externally, which is what this
controller does.

This controller "`linkerd-reinitialize-pods`" watches over events on
pods in the current node, which have been injected but are in a
terminated state and whose `linkerd-network-validator` container exited
with code 95, and proceeds to evict them so they can restart with a
proper network config.

The controller is to be deployed as an additional container in the
`linkerd-cni` DaemonSet (addressed in linkerd/linkerd2#xxx).

## TO-DOs

- Figure why `/metrics` is returning a 404 (should show process metrics)
- Integration test

.github/workflows/release-reinitialize-pods.yml

@@ -0,0 +1,63 @@
+name: reinitialize-pods release
+
+on:
+  pull_request:
+    paths:
+      - .github/workflows/release-reinitialize-pods.yml
+  push:
+    tags: ["reinitialize-pods/v*"]
+
+permissions:
+  contents: read
+
+jobs:
+  meta:
+    timeout-minutes: 15
+    runs-on: ubuntu-latest
+    container: ghcr.io/linkerd/dev:v42-rust
+    steps:
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+      - uses: ./.github/actions/version-mode
+        id: meta
+        with:
+          package: reinitialize-pods
+          check: true
+    outputs:
+      repo: ${{ steps.meta.outputs.repo }}
+      mode: ${{ steps.meta.outputs.mode }}
+      version: ${{ steps.meta.outputs.version }}
+
+  package:
+    needs: meta
+    strategy:
+      matrix:
+        arch: [amd64, arm64, arm]
+    timeout-minutes: 10
+    runs-on: ubuntu-latest
+    container: ghcr.io/linkerd/dev:v42-rust-musl
+    steps:
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+      - run: just reinitialize-pods arch=${{ matrix.arch }} profile=release version=${{ needs.meta.outputs.version }} package
+      - uses: actions/upload-artifact@v3
+        with:
+          name: ${{ matrix.arch }}-artifacts
+          path: target/package/
+
+  publish:
+    needs: [meta, package]
+    timeout-minutes: 5
+    permissions:
+      contents: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a
+        with:
+          path: ${{ runner.temp }}/artifacts
+      - run: find "$RUNNER_TEMP"/artifacts -type f -ls
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+      - if: needs.meta.outputs.mode == 'release'
+        uses: softprops/action-gh-release@de2c0eb89ae2a093876385947365aca7b0e5f844
+        with:
+          name: validator ${{ needs.meta.outputs.version }}
+          files: ${{ runner.temp }}/artifacts/**/*
+