Support reading filter expression from file

[mouchar]

I'd like to pass expression as a file, the same way as I can with similar tools (jq -f program-file, awk -f file,...). As -f option already serves another purpose, a new option --from-file filter-file borrowed from jq would be fine.

This option could also allow me to pass filter using bash process substitution, like in yq e --from-file <(generate-yq-filter.sh) /path/to/file.yaml, to avoid unnecessary temporary files if the filter needs to be generated.

It would also resolve various issues with special characters, shell-quoting troubles, and so on.

[mikefarah]

Related: #1103 - I think there's enough people asking for this to add it - will add in the next release

[mikefarah]

Fixed in 4.22.1