rename section to match new ramble interface

[becker33]

Ramble interface changed spack to software in one spot

Question: do we update our internals to match, or only update our outputs.

This PR only does the outputs, but we could update the internals as well

[pearce8]

Re: do we update our internals to match. We will need to be able to use pip for some of the packages (incomplete example: #283). Will that force us to update our internals? @becker33

[becker33]

No -- currently we have a method called compute_spack_section, and what it computes is put into a section named software. We can rename the method to compute_software_section but I just don't like the new ramble name, so I didn't immediately jump on doing that.

[pearce8]

I am fine with leaving it as compute_spack_section.