checksrc-all: rewrite in Perl, remove checksrc.bat

`checksrc.bat` was outdated and required Perl for `checksrc.pl` anyway.
Rewrite `checksrc-all.sh` in Perl, making it usable in envs without
a POSIX shell.

Closes #17882

.github/workflows/checksrc.yml

@@ -43,7 +43,7 @@ jobs:
           persist-credentials: false
 
       - name: 'check'
-        run: scripts/checksrc-all.sh
+        run: scripts/checksrc-all.pl
 
   codespell-cmakelint-pytype-ruff:
     name: 'codespell, cmakelint, pytype, ruff'

.github/workflows/distcheck.yml

@@ -113,7 +113,7 @@ jobs:
           make test-ci
           make install
           popd
-          scripts/checksrc-all.sh
+          scripts/checksrc-all.pl
 
   verify-out-of-tree-cmake:
     name: 'CM out-of-tree'