Create function to manage cache

[rafapereirabr]

Brief description of the problem:

Now that we are storing R5 Jar at tools::R_user_dir("r5r", which = "cache"), CRAN requires that we have a function that allows users to 'manage' the cache dir.

Proposed solution

I'm planning to create the r5r_chache() function. I'm glad to hear suggestions of other names for this function. Anyway, the function will work pretty much like censobr::censobr_cache()

Here is how censobr_cache()works. It has only two parameters:

censobr_cache(list_files = TRUE, delete_file = NULL)

• list_files: Logical. Whether to print a message with the address of all censobr data sets cached locally. Defaults to TRUE.
• delete_file: String. The file name (basename) of a censobr data set cached locally that should be deleted. Defaults to NULL, so that no file is deleted. If delete_file = "all", then all cached censobr files are deleted