WIP Adding "volume" aka "workspace" declaration to Tasks

[bobcatfish]

Changes

So far just docs and examples for declaring volumes in a Task via the
"workspace" field and binding to them at runtime. This is midway between
@skaegi's proposal b/c it allows the user to bring their own PVC but
isn't the full cadillac version because it does not include volume
devices.

@skaegi what do you think so far?

(Will eventually fix #1438)

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Release Notes

TBD

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[bobcatfish]

Got some great feedback from @skaegi , gonna close this for now and open a new PR with some updates.