Revamp Github CI/CD and Cleanup Outdated Contents

Summary:
Followup to  facebookincubator/TTPForge#446 but for ForgeArmory instead of TTPForge.

Read this bullets top-to-bottom - they match the ordering of changed files in this diff:

* Remove renovate, as we are no longer using it after moving to fbcode
* Remove executable file permissions from files that don't need them
* Remove Golang hooks that don't apply to this repository
* Remove YAML linters that aren't compatible with TTPForge template format
* Remove YAML schema, as it is incomplete and unmaintained, and has been replaced by facebookincubator/TTPForge#475
* Remove mage, as it is not required due to reduced dependency count (in the same manner that it was removed in the corresponding PR against TTPForge)
* Remove other files (asdf, tool-versions, etc) that are no longer needed due to simplified dependencies
* Remove obsolete docs and examples
* Update README.md to reference canonical documentation and reflect developer workflow simplification

Differential Revision: D51814055

fbshipit-source-id: 54c5e6bd9f8bf0823f12bbbaa9d82bc82811902d

.github/workflows/pre-commit.yaml

@@ -5,54 +5,14 @@ on:
     types:
       - opened
       - synchronize
-  # Run once a week (see https://crontab.guru)
-  schedule:
-    - cron: "0 0 * * 0"
-  workflow_dispatch:
 jobs:
   pre-commit:
     name: Update pre-commit hooks and run pre-commit
     runs-on: ubuntu-latest
     steps:
-      - name: Set up git repository
-        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
-
-      - name: Set up BATS
-        uses: mig4/setup-bats@af9a00deb21b5d795cabfeaa8d9060410377686d # v1
-        with:
-          bats-version: 1.2.1
-
-      - name: Set up Python
-        uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # v4
-        with:
-          python-version: "3.x"
-
-      - name: Set up Go
-        uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4
-        with:
-          go-version: "1.21.0"
-
-      - name: Install go module dependencies
-        run: |
-          go install mvdan.cc/sh/v3/cmd/shfmt@latest
-          go install github.com/magefile/mage@latest
-
+      - name: Checkout Git repository
+        uses: actions/checkout@v4
       - name: Install pre-commit
         run: pip3 install pre-commit
-
-      - name: Run go mod tidy - necessary to avoid errors with renovatebot PRs
-        run: pushd magefiles; go mod tidy; popd
-
-      - name: Commit go.mod and go.sum changes to keep pre-commit happy
-        run: |
-          git config --global user.email "[email protected]"
-          git config --global user.name "GitHub Action"
-          git add magefiles/go.mod magefiles/go.sum
-          git diff --quiet && git diff --staged --quiet || \
-            git commit -m "Update go.mod and go.sum"
-
-      - name: Install pre-commit dependencies
-        run: mage installDeps
-
       - name: Run pre-commit
-        run: mage runPreCommit
+        run: pre-commit run --all-files