Add a `Makefile` to automate common command-line tasks

[Raruto]

List of changes:

Added files:

• Makefile *
• Makefile.assets.mk
• Makefile.tasks.mk
• Makefile.semver.mk (not included in VCS, remotely downloaded) *
• Makefile.venv.mk (not included in VCS, remotely downloaded) *

* additional implementation notes: g3w-suite/makefiles

Deprecated files:

• ci_scripts/build_suite.sh replaced by: make g3w-admin/core/static/bower_components

• ci_scripts/run_env_development.sh replaced by: make run-docker

• ci_scripts/setup_suite.sh replaced by: make setup-suite

• pavement.py replaced by: make install and make runserver

• run_docker_tests.sh replaced by: make tests

Refer to the Makefile.assets.mk and Makefile.tasks.mk files for more information about these deprecated files

TODO:

• [ ] find out how to remove gulpfile.js dependency (ref: make build-assets)
• [ ] figure out what happened to the following file: ci_scripts/Dockerfile.local-develpment-ubuntu-2004.dockerfile (ref: make build-docker and make run-docker)
• [ ] update / remove ci_scripts/README.md
• [ ] add / update contributing section within README.md
• [ ] do some additional in-depth testing on all the docker related scripts (eg. make tests)
• [x] update .github/workflows/test_runner.yml file in order to use make tasks
• [ ] write a make killserver task in order to replace the paver kill task (from pavement.py) or deprecate the background parameter inside the make runserver [ foreground = "set any value to disable background" ]
• [ ] do some in-depth tests on all tasks related to the creation and use of the virtual environment (ref. Makefile.venv.mk)
• [ ] make use of virtual enviroment binaries instead of the global ones within Makefile.tasks.mk (eg. adding export PATH := $(VENV_BIN):$(PATH) before declaring PYTHON and PIP variables ? ref: httpie/Makefile#L13-L22)

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Closes: https://github.com/g3w-suite/g3w-admin/issues/431

Related to: https://github.com/g3w-suite/g3w-admin/issues/419, https://github.com/g3w-suite/g3w-admin/issues/434, https://github.com/g3w-suite/g3w-admin/issues/380, https://github.com/g3w-suite/g3w-admin/issues/373