LU-15565 utils: updated lfs getstripe yaml format

LU-15565 utils: updated lfs getstripe yaml format

For composite files 'lfs getstripe --yaml' used a key for each
component rather than an array. This hindered the use of the
output with common YAML tooling. The leading spaces meant users
needed to pre-process the output for seemingly no reason. Each
component also had the id harcoded into the name rather than
using a more flexible list ('components:').

'lfs setstripe --yaml YAML_FILE file|dir' is still compatible
with the previous YAML format incase there were stored files
being used.

The new YAML formatting has been check with results from
"https://zhwt.github.io/yaml-to-go/".

Modified the argument parsing in 'lfs_migrate' to be more
robust as it was failing tests 56[w[a-c],x[b,c]].

Signed-off-by: Frederick Dilger <fdilger@whamcloud.com>
Change-Id: I50ff4ebd9413fb66f05647c11542f7ce9f1ba879
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55311
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>