Update "create new" action

[ocdtrekkie]

Davros currently relies on a messy hack in Sandstorm to generate the "Create new shared directory" text, as nounPhrase was implemented over eight years ago: https://github.com/sandstorm-io/sandstorm/blob/2b0bcfa0a0eec3b9b0c7de9c80161c9eb165a052/shell/imports/sandstorm-db/db.js#L2381-L2412

The comment describes a desire to remove this hack, so we should update apps which rely on it to set this. Additionally, Tempest is not supporting this legacy hack, so this patch will improve Davros support in Tempest.

We might not fix this with every package, but since Davros tends to be pretty heavily used, and there's already a few good fixes in the wings for it's next release, I wanted to get this PR open.

cc: @zenhack

[zenhack]

To clarify re: tempest, "not supported" means it will just use "grain" for things that don't have nounPhrase set, rather than jump through hoops to infer something better like "shared directory."