Add a --basic flag to the create-react-admin package to skip interactive steps

[erwanMarmelab]

Problem

To get a non-interactive `create-react-admin`, one must pass all options:

npx create-react-admin my-admin -- \
  --data-provider none
  --auth-provider none
  --resource skip
  --install skip

This is super verbose, especially in documentation.

Solution

Add a --basic option that replaces all the others

npm init react-admin test-admin1 -- --basic

How To Test

On the xx branch, build the cli:

make build-create-react-admin

Create a new project with npx:

npx create-react-admin test-admin-npx -- \
  --data-provider none
  --auth-provider none
  --resource skip
  --install skip

Create another one with the local version of the cli:

./node_modules/.bin/create-react-admin test-admin-local --basic

Compare folders:

diff test-admin-npx test-admin-local

Additional Checks

• The PR targets master for a bugfix, or next for a feature
• [ ] The PR includes unit tests (if not possible, describe why)
• [ ] The PR includes one or several stories (if not possible, describe why)
• The documentation is up to date (cli doc with help flag)
• [ ] The documentation is up to date

[djhi]

You can avoid an else if by declaring local dataProvider, authProvider, resource and skip variables, initialize them depending on the cli.flags and then render the App

[djhi]

After testing, I notice that the generated App.tsx file still contains the guessers imports but they are not used anymore. You should modify generateAppFile.ts accordingly.

[fzaninotto]

After testing, I notice that the generated App.tsx file still contains the guessers imports but they are not used anymore. You should modify generateAppFile.ts accordingly.

I don't think that's a regression caused by this PR, plus it may be useful for beginners (and for the tutorial).