Bad Floating Point Format in Cost File

Update format for uptime, cost & stack_cost. Changed default value for
resource (Instance Type) to 'unknown'. Created script (format-csv) to
fix the formats of the existing cost files.

ISSUE: RELENG-2715
Change-Id: Ibd8464faa1ba3983bf1e8ef5cd484d2f24c26e31
Signed-off-by: Tim Johnson <tijohnson@linuxfoundation.org>