Stock implementation

[erichartline]

• [x] Fix input graphql schema
• [x] Generate stock resolvers
• [x] Add CLI flags
• [x] Fill them out

Problems: A number of fields cannot be retrieved from backend yet

• for unshared, keep empty or fill with fake info (empty string)
• for shared, keep empty

[erichartline]

Known bugs:

• ListStrains and ListPlasmids require all three parameters (cursor, limit, filter) to be provided, otherwise it errors out.
• Plasmids and strains are created with random IDs, even if one is specified in the mutation.
• Server shuts down if attempting to get nonexistent strain/plasmid by ID. This can be fixed by returning an error message server side if m.NotFound = true, but this may not be optimal.

Update resolvers are still a work in progress.

[erichartline]

Latest update:

• The updated resolvers have been implemented. I handled them similarly to the creation resolvers in that I set up functions that loop over the input fields (using 'structs) and return a map with their values. Then I usemapstructure` to decode that into the necessary output structure.
• I fixed the bug where the server would shut down when trying to look up a nonexistent stock ID. The problem was server side where the m.NotFound checks were trying to return an error they did not have access to. I wrote a custom error message to replace them.
• The option to create stock with ID has been removed.

[erichartline]

Current issues:

• [x] UpdatePlasmid crashes the server if one of the optional plasmid_properties fields isn't included.
• [x] ListStrains and ListPlasmids require all three parameters to be provided. One possible way around this is to use an input object within the schema instead of three separate parameters.
• [x] The list resolvers need to have NextCursor and PreviousCursor implemented.