Create and edit stock transaction flow

[horvathmarton]

Description

We need a way for the user to create, edit and delete stock transactions on their own portfolios.

Technical details

• The API endpoints already exist here (POST/PUT/DELETE /transactions/stocks)
• The payload format is { ticker: string; amount: number (int); price: number; date: Date; portfolio: number (ID); comment?: string }
• [x] The functionality should be placed on the portfolio view.
• [x] Probably a modal is the easiest way to introduce the creation flow, but other ideas are also welcome (e.g.: a placeholder at the end of the table).
• [x] If a specific portfolio is selected at the top-right controls the portfolio should be automatically set during the creation flow, if the summary is selected, the user should select which portfolio is targeted.
• [x] Loading state should be handled properly.
• [x] Possible errors:
  • [x] 400 - malformed payload
  • [x] ~401 - the user is not autheticated~ (this is a possible error, but should not happen in this state of the frontend)
  • [x] 403 - the user is not allowed to create a position (for the selected portfolio)
  • [x] 500 - unhandled error

[horvathmarton]

With the current API, we couldn't create a transaction edit and delete flow, because we don't send any transaction info (just a summary). At the moment we leave it as is, but we should open a new issue that requires both BE and FE work, so the user could edit and delete stock transactions.