Estimated realized inflation

Pull Request Summary

Estimated realized inflation calculation (ref). The calculation calculates slope from first block of the current cycle till the current block and assumes the same slope until the end of the period. This estimation introduces an error which will decrease after stakers clam their rewards (after first build and earn subperiod) and decrease even more as we are approaching the end of the current cycle.

We have beens struggling how to display inflation with just one meaningful number and seems this is the best way so far. In the next iteration we plan to add inflation chart as defined in the document referenced above.

Check list

[ ] contains breaking changes
[x] adds new feature
[ ] modifies existing feature (bug fix or improvements)
[ ] relies on other tasks
[ ] documentation changes
[ ] tested on mobile devices

AstarNetwork / astar-apps

Estimated realized inflation #1280