Make automatic saving of results consider personalized folder structures

[csalcedo001]

Not all projects manage folder structures for results the same. Some organize results according to dates, some other according to run IDs or random hashes. It should be easy for the project structure to be setup on xLab.

[csalcedo001]

Potential solution:
Define a new string parameter for Setup class that represents the path to the save directory. This string will have {name} sub-strings inside that represent variables that will be replaced at the time of creating the directory, so that these names can be replaced with string formating. The set of variables will be pre-defined (don't know yet how to make it easily configurable by the user)

Some potential variables are:

• id: experiment ID
• time: shortcut for "Y-M-D_-h-m-s"
• date: shortcut for "Y-M-D"
• Y, year
• M, month
• D, day
• h, hour
• m, minute
• s, second
• hash: randomly generated hash

Examples:

• '{id}': Provides a folder 'runs/40/' for experiment with id=40.
• '{time}_{hash}': Could create a folder 'runs/2022-05-28_19-45-34_ajKpLTsA/'
• '{date}/{hash}': Could organize experiments in a folder structure that first groups experiment by date, and then assigns a random hash, like 'runs/2022-05-28/fUWnvDJq/'.