Add Lodash chunk and flatten to collection utils

[snsavage]

We have found a use for the Lodash flatten and chunk methods in a client project. Add them as methods in src/utilities/collection-utils.ts.

An alternative would be to make all Lodash methods available from AndcultureCode.JavaScript.Core.

The implementation in the client project has been tagged with this issue for reference.

[brandongregoryscott]

For reference, the approach to forwarding all of the lodash functions would be similar to the proposed issue on the testing repo: rsm-hcd/AndcultureCode.JavaScript.Testing#21, which would tack _ onto CoreUtils, CollectionUtils, or both