Support .rsync-filter when listing files

[harendra-kumar]

The patterns listed in the rsync-filter file should be honored if an option is on. This will be useful for listing files for backup. Similarly, we can also support .gitignore based filtering.

The file containing the rsync filtering patterns can be specified in the config. The syntax of the file can be found in the man page https://linux.die.net/man/1/rsync .