Add more aggregation options to camera stats tab

[sewardlee337]

Update to Issue #30

Select Aggregation Field widget has been re-enabled in the Camera stats tab, allowing for summing of image counts by Camera ID or Project ID. This functionality is enabled for the following options under the Select Statistic dropdown:

• Count of images
• Count of blank images
• Count of unknown images
• Count of uncatalogued images
• Count of wildlife images
• Count of human-related images

Aggregations for Average photos per deployment by either Camera ID or Project ID has not yet been implemented.

[sewardlee337]

Aggregations for Average photos per deployment by Camera ID and Project ID added in latest commit.