Introduce environment variable to disable Google docs file preview
web-frontend/modules/database/filePreviewTypes.js::GoogleDocFilePreview is added by default. This allows the user to preview PDF, word documents, powerpoint presentation directly in Baserow via a Google Docs iframe. Some user don't want this to be enabled because employees could accidentally open confidential files via Google Docs. This could be a security issue because Google will then download the files to their server.
It must be possible to easily disable this preview type via an environment variable. By default it must be enabled by default, but if this environment variable, maybe
BASEROW_DISABLE_GOOGLE_DOCS_FILE_PREVIEW, is true it should disable the google docs file preview entirely.