The global declaration supports displayers and a few other parameters, in this request we should also support global datasets declaration. At the least the following fields should be supported for all datasets:

• URL: Users may rely on a base URL for all the datasets
• Headers: Headers may be common for all datasets when using, for example, bearer tokens
• Type: the dataset type may be an unique one for all datasets
• cache: a user may want to configure global cache

Just like for displayers, a local dataset may override the global value