Import brew test-bot to Homebrew/brew.

While we're here, put it in its own module and cleanup now unused bits
of Homebrew code related to external tap commands (as this was the last
one).

Author: MikeMcQuaid

.github/workflows/actionlint.yml

@@ -38,7 +38,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Install tools
         run: brew install actionlint shellcheck zizmor

.github/workflows/autogenerated-files.yml

@@ -31,7 +31,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: true
 
       - name: Cache Bundler RubyGems
         uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0

.github/workflows/copilot-setup-steps.yml

@@ -21,7 +21,6 @@ jobs:
         with:
           core: true
           cask: true
-          test-bot: true
 
       - run: brew install-bundler-gems --groups=all
 

.github/workflows/docs.yml

@@ -28,7 +28,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Checkout repository
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

.github/workflows/doctor.yml

@@ -32,7 +32,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Determine runners to use for this job
         id: determine-runners
@@ -59,7 +58,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: true
 
       - run: brew test-bot --only-cleanup-before
         if: matrix.cleanup

.github/workflows/pkg-installer.yml

@@ -47,7 +47,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Install Pandoc
         run: brew install pandoc

.github/workflows/rubydoc.yml

@@ -33,7 +33,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Checkout Homebrew/rubydoc.brew.sh
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

.github/workflows/sbom.yml

@@ -28,7 +28,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Configure Git user
         uses: Homebrew/actions/git-user-config@main

.github/workflows/sorbet.yml

@@ -34,7 +34,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Configure Git user
         if: github.event_name != 'pull_request'

.github/workflows/spdx.yml

@@ -28,7 +28,6 @@ jobs:
         with:
           core: false
           cask: false
-          test-bot: false
 
       - name: Configure Git user
         uses: Homebrew/actions/git-user-config@main