Support unregistered reconstructions.

Support reconstructions in sample space. Allow viewing all unregistered reconstructions for a sample. A separate issue will describe transforming unregistered to registered (if needed).

- Upload unregistered data (swc/json)
- Using Reconstruct Neurons tab, if you are an annotator on a neuron/candidate there will be an option to upload reconstruction data
- The upload is similar to on the Review panel for registered data and reviewers, but does not need to run checks, have fields for duration, etc.
- The unregistered reconstruction will be assigned to the existing neuron, similar to a registered one, but will not be a part of the existing downstream behaviors (Review, Publish to portal, etc).
- Generate a precomputed skeleton for NG in a separate dataset (do we need mirror, separate axon/dendrite viewing support?)
- View unregistered reconstructions
- Add an option to view the unregistered reconstructions for the sample in NG below the sample table in place of or before the Neuron table
- Any requirements for filtering, e.g., soma compartment based on the one entered for the candidate neuron?