Add the Create cluster button dropdown

[mendaomn]

Description

This PR adds the Create cluster button dropdown, to be adopted in a future PR.

It follows the work done with #90 and #84

Changes

• add CreateButtonDropdown component
• connect the dropdown options to the HiddenFileUpload and the FromClusterModal

Screenshot

How Has This Been Tested?

• manually
• unit test
• file upload will be tested with e2e tests once the CreateButtonDropdown will be adopted

PR Quality Checklist

• I added tests to new or existing code
• I removed hardcoded strings and used react-i18next library (useTranslation hook and/or Trans component), see an example here
• I made sure no sensitive info gets logged at any time in the codebase (see here) (e.g. no user info or details, no stacktraces, etc.)
• I checked that infrastructure/update_infrastructure.sh runs without any error
• I checked that npm run build builds without any error
• I checked that clusters are listed correctly
• I checked that a new cluster can be created (config is produced and dry run passes)
• I checked that login and logout work as expected

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[mtfranchetto]

Great work @mendaomn !