Implement User Table

# Why?

**As a** admin

**I want** track the lifecycle of a user

**So that** I can track user information.

Right now, all of this is contained within a retool table, which is ok for now.
This will become a problem if we want to migrate off of retool, which would mean we would need to migrate all of this into AWS.

# What?

Should just follow the schema of the retool user table.

https://a2nseattle.retool.com/resources/data/6fff4c43-51f0-4e0a-8c52-a053eb130abd/users?env=production

Would also want to add to CUD functions of other tables to make sure that the user table points to all associated records (i.e. that there's a list of all reservationIds from the user table).

# Additional context

Would want to do this in a couple of steps:
1. Create the new table & schema in DynamoDB (email should be primary key)
2. Create new APIs to `CreateUser`, `DeleteUser`
3. Create new API to `ChangeEmail` - You want this API to change what the email primary key is, but then also add the new email to the `emails` column. The `emails` column is all the different emails that a user has every had. Things might point to the old email, so we need this to be able to get things from old email addresses as well.
4. Create new `GetUser` API that will also return associated history, schedule, etc. information.
5. Have existing `History`, `Schedule`, `Item` CUD operations add/remove information from the user table.
6. Migrate Retool to use AWS table, including migrating table information to AWS
7. Clear Retool Resources