:gift: Depositor notifications

[ShanaLMoore]

Issue:

• https://github.com/scientist-softserv/palni-palci/issues/1020

TODO:

• [x] make email dynamic, including the date, tenant name, link to dashboard, etc
• [x] Do we want to make an option for the user to not receive emails? If so - we need UI work and possibly migrations. [update - this is now in the SOW and needs to be a separate ticket/work]
• [ ] How often Hyrax::UserStatImporter job run? - Is Rob setting up a job to run the rake task. Task needs to work for all tenants. [ update - not sure this matters for our sake ]
• [x] specs

[ShanaLMoore]

@laritakr @kirkkwang I can't approve this since I opened it, but it looks good! Thanks so much for completing this.