Add -R recursive option to fs ls command

[justinTM]

currently i'm just looping results of fs ls and appending results of command to the end of the root path before running the command again until i reach the file I'm looking for across all subdirectories.

what would be nice is a -R option to recursively list subdirectories of a DBFS path.

$ databricks fs ls -R --absolute "dbfs:/job-logs"
dbfs:/job-logs/0708-112403-f1tsd6as8/executor/app-20220708042345808-0000/0/stderr
dbfs:/job-logs/0708-112403-f1tsd6as8/executor/app-20220708042345808-0000/0/stdout
dbfs:/job-logs/0708-112403-f1tsd6as8/executor/app-20220708042345808-0000/1/stdout
dbfs:/job-logs/0708-112403-f1tsd6as8/executor/app-20220708042345808-0000/1/stderr

[justinTM]

#513