Merge branch '6-ci-episode-7-exercise-1-using-includes-updated' into 'ci-episode-7-exercise-1-using-includes'

Improve consistency with workshop materials and example project for episode 7 - using includes

See merge request hifis/software/education/hifis-workshops/gitlab-ci/exercise-project!24

* make sure installation works fine with more recent Debian versions
* Use googletest 1.14.0
* get rid of CMAKE CMP0135 warning

Upgrade Python and Gcc Docker images used

See merge request hifis/software/education/hifis-workshops/gitlab-ci/exercise-project!19

* To fix the CI pipeline the Docker images are upgraded.

* Use Python 3.10.
* Add stages to pipeline.
* Introduce new file to be included locally and move default keyword
and extensions into that new file.
* Add stage keyword to all CI jobs.
* Reorder keywords in CI jobs that use extends keyword.
* Use full relative path to executable when calling app.
* Use needs keyword to define dependencies.
* Use artifacts sub-key of nedds keyword in favour of dependencies
keyword.

* Add reference solution for exercise 1 in episode 7 regarding using
includes to restructure the CI pipeline and splitting it up into
multiple files.

* Use python:3.11 image and gcc:11 and gcc:12 image in CI pipeline.
* GoogleTest v1.13.0 supports only C++ >= 14. This requirement is
  not met with gcc:10, hence remove CI jobs with gcc:10 image.

* Use stages instead of a pure stageless pipeline while still using the
needs keyword to reorder execution of CI jobs.

* Ues Python 3.10.
* Reorder keywords when extends keyword is used.
* Use full relative path to call exercise app.
* Use artifacts sub-key of needs keyword.
* Remove dependencies keyword from CI jobs in favour of needs sub-key
artifacts.
* Remove needs keywords that are not necessary because there are no
dependencies.

* Reference solution for exericse 1 in episode 6 uses a stageless
pipeline and the interruptible keyword.

* Use python:3.11 image and gcc:11 and gcc:12 image in CI pipeline.
* GoogleTest v1.13.0 supports only C++ >= 14. This requirement is
  not met with gcc:10, hence remove CI jobs with gcc:10 image.

* Reorder keywords in CI jobs and put extends keyword first.
* Use Python 3.10 as default base image.
* Use full path to executable of exercise app when calling app.

* Remove redundancies from CI pipeline by using defaults, extends
and matrix keywords.

* Use python:3.11 image and gcc:11 and gcc:12 image in CI pipeline.
* GoogleTest v1.13.0 supports only C++ >= 14. This requirement is not
  met with gcc:10, hence remove CI jobs with gcc:10 image.

* Use Python 3.10 as base images.
* Change path to executable when calling exercise app in job run.

* New CI jobs are license_compliance, lint, build, test, run.

* Re-add CI pipeline with initial CI job that builds and runs the
application.

Adapt README regarding CMake minimum version

See merge request hifis/software/education/hifis-workshops/gitlab-ci/exercise-project!18

* CMake minimum version has been decreased.

Downgrade CMake requirements to 3.14

See merge request hifis/software/education/hifis-workshops/gitlab-ci/exercise-project!17

* CMake need not be used in the lastest version 3.26.

Update project dependencies like cmake and cpp

Closes #4

See merge request hifis/software/education/hifis-workshops/gitlab-ci/exercise-project!12

* Update information in file README and file CMakeLists.txt to use cmake
  3.26 and C++14.
* Add information on how to install cmake.
* Use different GoggleTest URL for newest Git tag v1.13.0.

Fix instructions in file README

Closes #2

See merge request hifis/software/education/gitlab-ci/exercise-project!10

* Built executable is located in folder ./build/bin/ now.

Put executable into bin directory during build

See merge request hifis/software/education/gitlab-ci/exercise-project!4

* The built executable should be put into the bin folder.

Fix linting violations and errors in cmake project

Closes #1

See merge request hifis/software/education/gitlab-ci/exercise-project!2

* Fixed style guide violations detected by cpplint.
* Fixed errors in the cmake project when building the project.