[TS] Add generic typings for schemas

[Convly]

What does it do?

Add generic typings for schemas and attributes.

Why is it needed?

This is the first step to adding more and more typings to the core Strapi elements.

⚠️ This PR has been developed using Typescript 4.7.

VSCode hasn't released a compatible version of its editor yet (it should be out very early June 2022). In the meantime, please consider using VSCode insider to test this branch. For more information/context, please see this comment

The topic mentioned above is no longer true as the 4.7 parts of the code have been moved to another PR that will be merged later once TS 4.7 will be more available in the ecosystem

[Bassel17]

it seems we also have some unit tests failing but it doesn't seem to be related to this PR, the same tests are failing on features/typescript

[codecov]

Codecov Report

Merging #13416 (40875d4) into features/typescript (bdb5a3e) will increase coverage by 5.40%.
The diff coverage is n/a.

@@                   Coverage Diff                   @@
##           features/typescript   #13416      +/-   ##
=======================================================
+ Coverage                48.83%   54.23%   +5.40%     
=======================================================
  Files                      259     1217     +958     
  Lines                     9115    30804   +21689     
  Branches                  2036     5597    +3561     
=======================================================
+ Hits                      4451    16706   +12255     
- Misses                    3839    12261    +8422     
- Partials                   825     1837    +1012     

Flag	Coverage Δ
front	56.50% <ø> (?)
unit	48.83% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
packages/core/upload/admin/src/hooks/useUpload.js	54.83% <0.00%> (ø)
...min/src/components/ConfigurationsProvider/index.js	100.00% <0.00%> (ø)
...aManagerProvider/utils/retrieveNestedComponents.js	100.00% <0.00%> (ø)
...ntent-manager/pages/EditView/Informations/index.js	100.00% <0.00%> (ø)
.../content-manager/components/SelectWrapper/index.js	23.30% <0.00%> (ø)
...njectedComponents/CMEditViewLocalePicker/Bullet.js	0.00% <0.00%> (ø)
...ager/pages/ListSettingsView/components/Settings.js	74.28% <0.00%> (ø)
...ugins/i18n/admin/src/components/ModalEdit/index.js	0.00% <0.00%> (ø)
...-permissions/admin/src/hooks/usePlugins/reducer.js	100.00% <0.00%> (ø)
...ontent-manager/pages/ListSettingsView/utils/api.js	80.00% <0.00%> (ø)
... and 948 more

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[alexandrebodin]

Nice job it starting to take form 👍

[alexandrebodin]

LGTM

[strapi-bot]

This pull request has been mentioned on Strapi Community Forum. There might be relevant details there:

https://forum.strapi.io/t/strapi-second-beta-release-for-v-4-3-0/20170/1