Document the project and file upload limits in pypi on the FAQ page

[SurenNihalani]

This is for #6192 . I had to create a new constants module because import warehouse.legacy leads to circular imports. Instead of resolving that, I went with creating a new file

Test Plan:
make build, make initdb, make serve and read http://localhost/help/#project-size-limit .

This is how it looks like:

Fixes #6192.

[di]

From #6192 (comment):

I'd prefer using the variables to control the output so as to prevent drift between the values and the docs.

I think I agree, these variables can be found here:

warehouse/warehouse/forklift/legacy.py

Lines 78 to 80 in 281447f

	MAX_FILESIZE = 100 * ONE_MB
	MAX_SIGSIZE = 8 * 1024
	MAX_PROJECT_SIZE = 10 * ONE_GB

[SurenNihalani]

@di , updated the PR. Thanks for the suggestion. Please review if you have cycles

[SurenNihalani]

Does anyone know why this is awaiting response? This should be ready for review

[di]

We should make sure that this is the source of truth to these values everywhere, so instead of using MAX_FILESIZE and MAX_PROJECT_SIZE outside of this file, we should use the values from settings.

[di]

Hi @SurenNihalani, are you able to resolve the conflicts here and address the review so we can merge this? Thanks!