Archive logs to separate folder

#### Feature Description

Consul logs files are archived in same location as they are created , thus making the folder crowded. For someone wanting to keep only latest file and move rest to an archive folder does not have any option.

For backward compatibility, this location would be an optional feature and if not provided, consul will work as before.

Such option is provided by other logging frameworks like NLog, Log4Net etc.

#### Use Case(s)

This feature will be beneficial for logs monitoring software to focus only 1 file (as rest will be in another folder). Currently its not possible as log file do not have fixed names (unix time is appended to log file name) that's why such softwares need to be provided filters like \*.log or Consul\*.log.

I'll be happy to raise a PR if this feature looks useful.