Add GitLab CI/CD support (#2163)

* Use GitLab CI/CD

* Force colored tests

* Get rid of an error

* Mark tests as slow

* Disable codecov & coveralls

* Python 3.5-3.8

* Add Python 3.4

* Support both OpenSSL 1.1.0 and 1.1.1+

* Test both OpenSSL 1.1.0 and 1.1.1+

* Fix OpenSSL 1.1.1

* Fix Python 3.4 build

.gitlab-ci.yml

@@ -0,0 +1,48 @@
+stages:
+  - test
+
+.test_template: &test_template
+  stage: test
+  before_script:
+    - pip install --upgrade pip wheel
+    # Selenium and requests can't be installed without a requests hint on Python 3.4
+    - pip install --upgrade requests>=2.22.0
+    - pip install --upgrade codecov coveralls flake8 mock pytest==4.6.3 pytest-cov selenium
+    - pip install --upgrade -r requirements.txt
+  script:
+    - pip list
+    - openssl version -a
+    - python -m pytest -x plugins/CryptMessage/Test --color=yes
+    - python -m pytest -x plugins/Bigfile/Test --color=yes
+    - python -m pytest -x plugins/AnnounceLocal/Test --color=yes
+    - python -m pytest -x plugins/OptionalManager/Test --color=yes
+    - python -m pytest src/Test --cov=src --cov-config src/Test/coverage.ini --color=yes
+    - mv plugins/disabled-Multiuser plugins/Multiuser
+    - python -m pytest -x plugins/Multiuser/Test --color=yes
+    - mv plugins/disabled-Bootstrapper plugins/Bootstrapper
+    - python -m pytest -x plugins/Bootstrapper/Test --color=yes
+    - flake8 . --count --select=E9,F63,F72,F82 --show-source --statistics --exclude=src/lib/pybitcointools/
+
+test:py3.4:
+  image: python:3.4.3
+  <<: *test_template
+
+test:py3.5:
+  image: python:3.5.7
+  <<: *test_template
+
+test:py3.6:
+  image: python:3.6.9
+  <<: *test_template
+
+test:py3.7-openssl1.1.0:
+  image: python:3.7.0b5
+  <<: *test_template
+
+test:py3.7-openssl1.1.1:
+  image: python:3.7.4
+  <<: *test_template
+
+test:py3.8:
+  image: python:3.8.0b3
+  <<: *test_template