CI: add whitespace checker

Fix issues detected.

Also:

- One of the `.vc` files used LF EOLs, while the other didn't.
  Make that one also use LF EOLs, as this is apparently supported by
  `nmake`.

- Drop `.dsw` and `.btn` types from `.gitattributes`.
  The repository doesn't use them.

- Sync section order with the rest of files in
  `tests/certs/EdelCurlRoot-ca.prm`.

- Indent/align `.prm` and `.pem` files.

- Delete dummy `[something]` section from `.prm` and `.pem` files.

Mental note:
MSVC `.sln` files seem to accept spaces for indentation and also support
LF line-endings. I cannot test this and I don't know what's more
convenient when updating them, so left them as-is, with specific
exclusions.

Closes #14031

.github/workflows/spacecheck.yml

@@ -0,0 +1,28 @@
+# Copyright (C) Viktor Szakats
+#
+# SPDX-License-Identifier: curl
+
+name: spacecheck
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
+permissions: {}
+
+jobs:
+  spacecheck:
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
+      - name: 'spacecheck'
+        run: .github/scripts/spacecheck.pl