[DO NOT MERGE] Upgrade wagtail v2.8 and django V3.0.3

[pkfec]

Summary (required)

Pillow is child pkg of Wagtail and the latest version of Wagtail v2.8 comes with the pillow v6.2.2. While updating wagtail, i noticed that the wagtail v2.8 is compatible with Django v3.0. So i went ahead and updated Django to latest v3.0.3.

• Resolves
  [Med] Snyk: Denial of Service (DoS) Due (03/08/2020) #3454
  [Snyk: High] SQL Injection (Due: 03/18/2020) #3529
  [Snyk: High] Integer Overflow (Due: 2/22/2020) #3482
  [Snyk: High] Buffer Overflow (Due: 2/22/2020) #3478
  Investigate Upgrading to Django 2.2 LTS #3105
  [Snyk] unlimited allocation of resources #3396
  [SNYK] - Weak Password Recovery Mechanism #3422

Include a summary of proposed changes.

1. remove the pkg called six thats not required. SET_NULL on delete flag
2. django3.0.3 - django.core.urlresolvers is deprecated. Replace it with django.urls
3. As of Django 1.9, the old way of including the admin urls is deprecated. pass admin.site.urls directly to url(), without the call to include().
4. {% load staticfiles %} is deprecated in Django 2.1, and removed in Django 3.0. Replaced {% load staticfiles %} tag with {% load static %} in template files.
5. Django 3.0.3: ForeignKey field requires on_delete argument
6. Django 2.0 has dropped support for old-style middleware classes in MIDDLEWARE_CLASSES. Renamed it as MIDDLEWARE.
7. Upgrade Wagtail v2.8, Django v3.0.3, Django-jinja v2.5.0

Impacted areas of the application

• wagtail interface
• fec-cms app

How to test

1. checkout the feature/3454-pkg-upgrade
2. create a new python virtual environment
3. run pip install -r requirements.txt
4. drop your local cfmd_cms_test db
5. create cfdm_cms_test db
6. download the latest wagtail pg dump file from shared drive
7. run pg_restore cmd to load this dump file on to your local cfdm_test_db
8. run ./manage.py makemigration
9. run ./manage.py migrate
10. run pytest under fec-cms folder
11. run pytest under fec-cms/fec folder
12. start server (./manage.py runserver)
13. Login to your local wagtail : http://127.0.0.1:8000/admin/login/
14. Add/Edit wagtail pages
15. export FEC_API_URL to dev, stage or prod and test the API endpoints on your local server http://127.0.0.1:8000/

[johnnyporkchops]

We should push this to feature space so we can have content team do a through test of Wagtail functionality.

[johnnyporkchops]

Although we do not have to, it may actually be helpful to squash migrations before makemigrations for this PR because it would remove migrations that cancel each other out . For example"
0006_auto_20150819_0546.py creates OptionsPage model....
0013_auto_20160427_2133.py removes OptionsPage model

[pkfec]

We should push this to feature space so we can have content team do a through test of Wagtail functionality.

@johnnyporkchops I second that. I would want you and @patphongs go over the changes in the PR first and approve before i push this branch to feature space

[patphongs]

@pkfec I recommend upgrading to the long term support (LTS) versions of Django and Wagtail. This will ensure greater support especially for patches and fixes than a version that is not supported. Django 2.2 is LTS until 4/2022 and Wagtail 2.7 is LTS until 2/2021.

[pkfec]

@patphongs thanks for feedback. I am going to downgrade the wagtail and django pkg to the LTS version. I will submit a new PR with the LTS version of those packages.

[patphongs]

Please see my recommendation

[codecov-io]

Codecov Report

Merging #3536 into develop will decrease coverage by 0.01%.
The diff coverage is 75%.

@@             Coverage Diff             @@
##           develop    #3536      +/-   ##
===========================================
- Coverage    74.96%   74.94%   -0.02%     
===========================================
  Files          120      120              
  Lines         7377     7373       -4     
  Branches       642      642              
===========================================
- Hits          5530     5526       -4     
  Misses        1847     1847

Impacted Files	Coverage Δ
fec/fec/urls.py	77.27% <0%> (ø)	⬆️
fec/fec/tests/test_robots.py	95.23% <100%> (ø)	⬆️
fec/fec/settings/base.py	87.95% <100%> (ø)	⬆️
fec/home/models.py	87.43% <100%> (-0.13%)	⬇️

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[pkfec]

LTS versions of Wagtail v2.7 and Django v2.2.10 upgrades are being tracked in this PR #3536

Closing this PR.