Don't override local member data / support running jobs from Docker

@DSASanFrancisco/portal-members

Summary

• Don't override the local first_name and last_name with the data from national, unless our local data is empty. We had complaints that national is not responsive about updating this data in all places. We get old member records with the old information and replace what we have with what national sends. It is probably best that we don't do this.
• Update the Dockerfile for running the jobs locally in Docker.

NOTE: If you want to run the import_membership script locally, it can deadlock if you don't allocate enough memory for Docker locally (the default of 2GB is too low, I recommend 4-6GB).

• Also, I think this fixes the build because it won't fail to build the job docker image.