Change voucher types

[fowczarek]

I want to merge this change because, resolve #4317

Screenshots

Pull Request Checklist

1. Privileged views and APIs are guarded by proper permission checks.
2. All visible strings are translated with proper context.
3. All data-formatting is locale-aware (dates, numbers, and so on).
4. Database queries are optimized and the number of queries is constant.
5. Database migration files are up to date.
6. The changes are tested.
7. The code is documented (docstrings, project documentation).
8. GraphQL schema and type definitions are up to date.
9. Changes are mentioned in the changelog.

[NyanKiyoshi]

Are you planning on adding a migration?

[fowczarek]

Are you planning on adding a migration?

This pull request has "In progress" label. I adding migrations after final rebase.

[codecov]

Codecov Report

Merging #4344 into master will increase coverage by <.01%.
The diff coverage is 94.73%.

@@            Coverage Diff             @@
##           master    #4344      +/-   ##
==========================================
+ Coverage   91.96%   91.97%   +<.01%     
==========================================
  Files         285      285              
  Lines       15911    15945      +34     
  Branches     1547     1553       +6     
==========================================
+ Hits        14633    14665      +32     
- Misses        873      874       +1     
- Partials      405      406       +1

Impacted Files	Coverage Δ
saleor/dashboard/discount/views.py	72.64% <ø> (ø)	⬆️
saleor/discount/models.py	83.6% <ø> (ø)	⬆️
saleor/dashboard/order/utils.py	93.42% <100%> (ø)	⬆️
saleor/graphql/discount/mutations.py	98.18% <100%> (+0.03%)	⬆️
saleor/graphql/discount/enums.py	100% <100%> (ø)	⬆️
saleor/dashboard/discount/forms.py	98.05% <100%> (+0.28%)	⬆️
saleor/checkout/utils.py	83.33% <88.88%> (+0.13%)	⬆️

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[django-queries]

Here is the report for c4f2c25 (mirumee/saleor @ 4317/change_voucher_types)
Base comparison is 63f77c5.

No differences were found. (click me)

# api.benchmark checkout
  test name                           	left count 	right count
  ------------------------------------	-----------	-----------
  add billing address to checkout     	         41	         41
  add shipping to checkout            	          7	          7
  checkout payment charge             	         16	         16
  complete checkout                   	          6	          6
  create checkout                     	         45	         45

# api.benchmark homepage
  test name                           	left count 	right count
  ------------------------------------	-----------	-----------
  retrieve main menu                  	          5	          5
  retrieve product list               	          4	          4
  retrieve secondary menu             	          5	          5
  retrieve shop                       	          2	          2

# api.benchmark product
  test name                           	left count 	right count
  ------------------------------------	-----------	-----------
  product details                     	         13	         13

# api.benchmark variant
  test name                           	left count 	right count
  ------------------------------------	-----------	-----------
  retrieve variant list               	          9	          9

[NyanKiyoshi]

We need to migrate the discounts having VALUE to ENTIRE_ORDER