devops: remove self-hosted runners (#4524)

Turns out there's a way to abuse these self-hosted runners through pull-requests that mess with the YML files.
We'll move them to the private repo.

.github/workflows/build_firefox.yml

@@ -1,27 +0,0 @@
-name: build firefox
-
-on:
-  push:
-    branches:
-      - master
-    paths:
-      - '.github/workflows/build_firefox.yml'
-      - 'browser_patches/firefox/BUILD_NUMBER'
-
-env:
-  AZ_ACCOUNT_KEY: ${{ secrets.AZ_ACCOUNT_KEY }}
-  AZ_ACCOUNT_NAME: ${{ secrets.AZ_ACCOUNT_NAME }}
-  TELEGRAM_BOT_KEY: ${{ secrets.TELEGRAM_BOT_KEY }}
-
-jobs:
-  ubuntu_18_04:
-    name: Ubuntu 18.04
-    runs-on: [self-hosted, fast-ubuntu-18.04]
-    steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-node@v1
-      with:
-        node-version: 14
-    - uses: microsoft/playwright-github-action@v1
-    - run: ./browser_patches/checkout_build_archive_upload.sh firefox-ubuntu-18.04
-

.github/workflows/build_webkit.yml

@@ -1,28 +0,0 @@
-name: build webkit
-
-on:
-  push:
-    branches:
-      - master
-    paths:
-      - '.github/workflows/build_webkit.yml'
-      - 'browser_patches/webkit/BUILD_NUMBER'
-
-env:
-  AZ_ACCOUNT_KEY: ${{ secrets.AZ_ACCOUNT_KEY }}
-  AZ_ACCOUNT_NAME: ${{ secrets.AZ_ACCOUNT_NAME }}
-  TELEGRAM_BOT_KEY: ${{ secrets.TELEGRAM_BOT_KEY }}
-  DEBIAN_FRONTEND: "noninteractive"
-
-jobs:
-  ubuntu_18_04:
-    name: Ubuntu 18.04
-    runs-on: [self-hosted, fast-ubuntu-18.04]
-    steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-node@v1
-      with:
-        node-version: 14
-    - uses: microsoft/playwright-github-action@v1
-    - run: ./browser_patches/checkout_build_archive_upload.sh webkit-ubuntu-18.04
-

.github/workflows/mirror_chromium_to_cdn.yml

@@ -1,30 +0,0 @@
-name: mirror chromium
-
-on:
-  push:
-    branches:
-      - master
-    paths:
-      - '.github/workflows/mirror_chromium_to_cdn.yml'
-      - 'browser_patches/chromium/BUILD_NUMBER'
-
-env:
-  AZ_ACCOUNT_KEY: ${{ secrets.AZ_ACCOUNT_KEY }}
-  AZ_ACCOUNT_NAME: ${{ secrets.AZ_ACCOUNT_NAME }}
-  TELEGRAM_BOT_KEY: ${{ secrets.TELEGRAM_BOT_KEY }}
-  DEBIAN_FRONTEND: "noninteractive"
-
-jobs:
-  ubuntu_18_04:
-    name: all platforms
-    runs-on: [ubuntu-18.04]
-    steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-node@v1
-      with:
-        node-version: 14
-    - run: ./browser_patches/checkout_build_archive_upload.sh chromium-linux-mirror-to-cdn
-    - run: ./browser_patches/checkout_build_archive_upload.sh chromium-mac-mirror-to-cdn
-    - run: ./browser_patches/checkout_build_archive_upload.sh chromium-win32-mirror-to-cdn
-    - run: ./browser_patches/checkout_build_archive_upload.sh chromium-win64-mirror-to-cdn
-