eurosat_dataset() might be improved in code style and data design

[cregouby]

Hello,

Current situation

The function could have improved code style

[eurosat_dataset()](#122 ) has a code styling that inherits from other language and prevent readability and portability :

• use of sprintf() instead of glue:: styled message concatenation
• use of base R warning() and if (){stop()} instead of package functions runtime_error("") and value_error("")
• reuse existing message for consistency with other _dataset() functions and preventing specific translation of messages. Example is "Dataset not found. You can use download = TRUE to download it." , ...

The function could have improved data movement design

[eurosat_dataset()](#122 ) uses it's own data folder for archive caching instead of reusing the common torchvision cache folder.

Expected situation

• maximize reuse of existing messages,
• utils.R message functions, and consistent code-style with other _dataset() functions
• reuse the download_and_cache() function for consistent large file storage on end-user machine