ci: add code coverage reporting to CI pipeline

Update code coverage file handling in the Dockerfile to generate 
coverage reports properly. Change temporary coverage file name and 
exclude specific files from the report. Remove the temporary file 
after processing. Add steps to the CI pipeline to download and 
execute the Codecov uploader, ensuring coverage data is uploaded 
for analysis during the build stage.

.gitlab-ci.yml

@@ -13,6 +13,9 @@ build:
   stage: build
   script:
     - build
+    - curl -Os https://uploader.codecov.io/latest/linux/codecov
+    - chmod +x codecov
+    - ./codecov -t ${CODECOV_TOKEN} -R $CI_PROJECT_DIR -C $CI_COMMIT_SHA -r $CI_PROJECT_PATH
     - push
   artifacts:
     paths: