Run "make lint" and "make reformat" inside docker container

[shevelevs]

This is so that it's not necessary to install python3.6 on the host machine. See #4948 for details.
This is not yet finished, but just to get feedback before I try to do more

Couple of implementation notes:

• static container doesn't have python3.6 installed, so it looks like it's easier to just use python3.6 image from docker registry
• technically the python3.6 "build" cointainer doesn't need to be in docker-compose (it can be just used from Makefile via docker run directly)
• "docs" target is the thing that currently won't work, it needs some modifications because of recursive make calls

[shevelevs]

@di, let me know what you think. Works for me locally:

docker-compose run --rm build /opt/warehouse/src/.state/env/bin/flake8 .
docker-compose run --rm build /opt/warehouse/src/.state/env/bin/black --check warehouse/ tests/
All done! ✨ 🍰 ✨
340 files would be left unchanged.
docker-compose run --rm build /opt/warehouse/src/.state/env/bin/doc8 --allow-long-titles README.rst CONTRIBUTING.rst docs/ --ignore-path docs/_build/
Scanning...
Validating...
========
Total files scanned = 23
Total files ignored = 21
Total accumulated errors = 0
Detailed error counts:
    - CheckCarriageReturn = 0
    - CheckIndentationNoTab = 0
    - CheckMaxLineLength = 0
    - CheckNewlineEndOfFile = 0
    - CheckTrailingWhitespace = 0
    - CheckValidity = 0
# TODO: Figure out a solution to https://github.com/deezer/template-remover/issues/1
#       so we can remove extra_whitespace from below.
docker-compose run --rm build /opt/warehouse/src/.state/env/bin/html_lint.py --printfilename --disable=optional_tag,names,protocol,extra_whitespace,concerns_separation `find ./warehouse/templates -path ./warehouse/templates/legacy -prune -o -name '*.html' -print`
# We're not on Travis, so we should lint static files inside the static container
docker-compose run --rm static ./node_modules/.bin/eslint 'warehouse/static/js/**' '**.js' --ignore-pattern 'warehouse/static/js/vendor/**'
docker-compose run --rm static ./node_modules/.bin/sass-lint --verbose
✔ ~/workspace/pypa/warehouse [Issue4948_RunReformatInDocker|✚ 1⚑ 1] 
20:50 $ make reformat
docker-compose run --rm build /opt/warehouse/src/.state/env/bin/black warehouse/ tests/
All done! ✨ 🍰 ✨
340 files left unchanged.
✔ ~/workspace/pypa/warehouse [Issue4948_RunReformatInDocker|✚ 1⚑ 1] 
20:50 $ make docs
/Library/Developer/CommandLineTools/usr/bin/make -C docs/ doctest SPHINXOPTS="-W" RUN_IN_DOCKER="docker-compose run --rm build" SUBDIR=docs BINDIR=/opt/warehouse/src/.state/env/bin
docker-compose run --rm build  sphinx-build -b doctest -d _build/doctrees  -W docs _build/doctest
Running Sphinx v1.8.1
making output directory...
building [mo]: targets for 0 po files that are out of date
building [doctest]: targets for 20 source files that are out of date
updating environment: 20 added, 0 changed, 0 removed
reading sources... [100%] ui-principles                                                                           
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
running tests...

Doctest summary
===============
    0 tests
    0 failures in tests
    0 failures in setup code
    0 failures in cleanup code
build succeeded.

Testing of doctests in the sources finished, look at the results in _build/doctest/output.txt.
Testing of doctests in the sources finished, look at the  results in _build/doctest/output.txt.
/Library/Developer/CommandLineTools/usr/bin/make -C docs/ html SPHINXOPTS="-W" RUN_IN_DOCKER="docker-compose run --rm build" SUBDIR=docs BINDIR=/opt/warehouse/src/.state/env/bin
docker-compose run --rm build  sphinx-build -b html -d _build/doctrees  -W docs _build/html
Running Sphinx v1.8.1
making output directory...
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 20 source files that are out of date
updating environment: 20 added, 0 changed, 0 removed
reading sources... [100%] ui-principles                                                                           
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] ui-principles                                                                            
generating indices... genindex http-routingtable
writing additional pages... search
copying static files... done
copying extra files... done
dumping search index in English (code: en) ... done
dumping object inventory... done
build succeeded.

The HTML pages are in _build/html.

Build finished. The HTML pages are in _build/html.

[brainwane]

@shevelevs I'm so sorry for the delay in response!

Could I ask you to resolve the conflict with the Makefile, and then I'll nudge a reviewer?

Also, is there a chance we'll see you at PyCon North America in May, during the sprints?

Thanks and sorry again.

[brainwane]

@shevelevs Hi! Could you resolve the Makefile conflict, so I can get this reviewed? Thanks!

[sayanarijit]

@brainwane I resolved the conflicts here: #6205