Add ANSI links support with a "{file_link}" tag

[nojhan]

Would allow for a short name display of the file, with an hyperlink to some URL/command.

Configuration like log.file_link("file://{file}",clutchlog::label::path);, then "{file_link}" in the template.

Possible label tags:

• path ("/home/nojhan/file.ext"),
• basename ("file.ext"),
• basestrip ("file"),
• dirname ("nojhan"),
• dirbase ("nojhan/file.ext"),
• dirbasestrip ("nojhan/file").