Filters a CSV file containing metadata of GitHub repositories according to user-specified criteria.
The input file must be a valid CSV file produced by the 'metadata' command.
Repositories can be filtered using the following criteria:
* Size: repositories with a size (in kB) below a specified threshold are discarded.
* Age: repositories with an age (in days) below a specified threshold are discarded.
* Disabled: disabled repositories can be excluded.
* Non-code: repositories that do not contain source code can be excluded (for example, repositories containing only documentation, data, or binary files).
The filtered metadata are written to a new CSV file. By default, the output file name is the input file name with the suffix '.filtered.csv'.
Output CSV file format:
* all columns from the input file, plus:
* age: repository age in days, computed as the difference between the last push and the repository creation date;