ENH: register sample data

[lopezmt]

No description provided.

[jcfr]

@lopezmt Here is an updated topic.

Next steps:

• [ ] try to load the downloaded data in the respective module. Now tracked in Add tests for loading sample data in corresponding module #164
• update SampleData so that it remembers the last directory selected by the user.
• [ ] improve modules so that the last input directory or files is stored in settings. Now tracked in Improve modules to keep track of last input directory #165
• [ ] after user click on a button to download data and select a destination directory, make sure the settings key expected by the corresponding module is set. Now tracked in Improve modules to keep track of last input directory #165

[jcfr]

@bpaniagua Every module for which we provides sample data will have a "SampleData" tab with corresponding button to download the data.

• Data Importer

• SPHARM-PDM Generator

[jcfr]

I am moving forward with the integration. We will tweak in follow-up commits.