Add other methods to the database connector files

[escottalexander]

in packages/nextjs/services/database/ there are the following files:

metrics.ts
projects.ts
totalsByDate.ts
projectTotalsByDate.ts

One for each collection.
They currently each have a method for reading data from the collection but we will also need to write whole records to each collection.

This issue is for adding a method to each of those files that writes whole entries to each collection. If you are unfamiliar with firebase you can view a recent project that uses the same setup here: https://github.com/BuidlGuidl/grants.buidlguidl.com

We will add more methods to these files as it becomes clear which methods are useful but for now it would be nice to simply have write methods.

[escottalexander]

This will need heavier revision with the realization that OSO will be providing timestamped data.

[escottalexander]

@blahkheart Knocked this out in #11