process loan update

[djudjuu]

• started /docs folder with documentaton on how tables are used when a loan is created
• /docs for what is seen on the dashboards and where it is taken from
• store everyone who lends money to the borrower in loan_participants, with amount and apr. the retrieve this actilve_loans in the get-user-by-email-query. This allows the loans they are involved in (althought not all as due to autoinvestment we might miss some, but its a good start)
• calcualte the APY for lenders
• create two receivables: lender & supporter to match a payable and also retrieve those in active loans

TODO in next pr:

• calculate the APY for supporters
• update payables & receivables on a repayment (although they arent really used at the moment,

THOUGHT: we kind of not really use payables or receivables at the moment. We could also just do everything from loan-requests (and the schedule that is saved there). I should have thought a bit longer before starting to code all this. It doesnt hurt to change the stuff that is currently there though..

NOTE:

• loan-participants store the invested amount without interest. which does not change over time
• receivables store the total amount to be repaid (thus the pricipal + interest) and keep track of how much has been repaid etc
• all info in receivables (and payables) is derived from the loan-schedule

[djudjuu]

After having a conversation with GS today, I decided to move away from a lot that I did here. APYs will now be computed inside swarmai and passed along with the PortfolioUpdate. This is much cleaner and easier to do. I will redo this PR, making it as slim as possible