Case T-420/17: Judgment of the General Court of 23 September 2020 — Portigon v SRB (Economic and monetary union — Banking union — Single Resolution Mechanism for credit institutions and certain investment firms (SRM) — Single Resolution Fund (SRF) — Decision of the SRB on the calculation of the 2017 ex ante contributions — Action for annulment — Direct and individual concern — Admissibility — Essential procedural requirements — Authentication of the decision — Obligation to state reasons — Limitation of the temporal effects of the judgment)