[directory-size.sh] Support spaces in paths

[aroberts]

The current code emits directory label only up to the first space, due to the default behavior of awk. This change pulls in the rest of the line output from du into the label, so directories containing spaces are properly captured

[dswarbrick]

I was about to suggest using sed instead, e.g.

sed -E 's/^([0-9]+)[[:blank:]](.+)$/node_directory_size_bytes{directory="\2"} \1/'

• however we also should handle directories with double-quotes in their names. Currently, these would cause malformed metrics to be printed, since the double-quotes need to be escaped.

[aroberts]

@dswarbrick fair enough, implemented both

[dswarbrick]

Please sign off your commits to satisfy the DCO.

[aroberts]

removed comment; rebased with signoffs