Calculate the dividend leakage and internal transaction costs based on the raw numbers from the annual reports

[nicwortel]

To calculate the real cost of a portfolio, this website takes into account not just the TER as reported by the fund, but also 'hidden' costs such as dividend leakage and the transaction fees paid by the fund to buy and sell underlying assets.

This data is based on the analysis performed by @gerbenvl, but is difficult to reproduce and keep up-to-date. Therefor it is likely that the data currently shown on the website is incorrect and/or outdated, which impacts the usefulness of the results shown on the website.

The goal of this issue is to replace the calculated data with raw numbers (which can be verified in the annual reports provided by the funds) and to develop a way to calculate the dividend leakage and internal transaction costs in the model used by this website, based on the raw data.

• Decide which pieces of data we need to collect, such as
  • dividend income received
  • dividend tax paid
  • etc.
• Decide how we want to calculate these numbers, for example:
  • look only at the last available year
  • take the average of the last N years
  • how to deal with newer funds for which not all information is available yet (see WEBG en WEBN toevoegen #53 for example)
  • etc.
• Decide which metadata we need to store to make it easy to verify the data and keep it up-to-date, for example:
  • the URL where the source document can be found
  • the page / section where each piece of data can be found
  • etc.
• Decide how to store this in the data directory
  • should it be part of the funds.json file or stored in a separate file?
  • how should the JSON be structured
  • etc.
• Implement various calculators which turn the raw data into usable pieces of information
• Collect the required pieces of data from annual reports of all funds

The end result should be that all data used to calculate the dividend leakage and internal transaction costs is easily verifiable by someone without having to spend lots of time to read through the documents, and that it is easy to update the data when a new annual report is released.