Update remote temp spack manifest name to prevent ambiguity

[CodeGat]

See ACCESS-NRI/ACCESS-OM3#64, specifically ACCESS-NRI/ACCESS-OM3#64 (comment)

Background

When a large amount of prereleases from the same repository are created around the same time, there is a possibility of the remote, temporarily stored MODEL.spack.yaml to be overwritten before the spack env create call.

The PR

In this PR:

• We further disambiguate the temporary remote file name with the job id number - for example, access-om3-82974392347.spack.yaml, rather than just access-om3.spack.yaml

[atteggiani]

LGTM!