Enforce limit on issues found in static analysis

Implements new script (count-bugs.py) for peeking inside clang static
analyzer's report and print just a summary.

If number of detected bugs goes beyond the limit, script will return
with error code 1, thus failing the CI run.  The upper limit is set to
113, which is current result of static analysis in our CI environment
(local run is likely to indicate different number); upper limit will
be updated in time, as issues get fixed or new compiler (detecting more
bugs) will be introduced.

This commit includes also slight modifictaions to count-warnings.py
script, to keep the both scripts outputting in similar format.

.github/workflows/static.yml

@@ -12,7 +12,7 @@ jobs:
       - name: "Install packages"
         run: sudo apt-get install libsdl1.2-dev libsdl-net1.2-dev libsdl-sound1.2-dev python3-setuptools
       - name: "Install scan-build (Python version)"
-        run: sudo pip3 install scan-build
+        run: sudo pip3 install scan-build beautifulsoup4 html5lib
       - name: Build
         run: |
           # build steps
@@ -27,3 +27,9 @@ jobs:
         with:
           name: report
           path: report
+      - name: Summarize report
+        run: |
+          # summary
+          echo "Full report is included in build Artifacts"
+          echo
+          ./scripts/count-bugs.py report/*/index.html