Merge bitcoin#2537: [Doc] Reset release-notes.md template for 5.4

fbd0b9a [Doc] Reset release-notes.md template for 5.4 (random-zebra)

Pull request description:

  Move all DMN related documentation to a temporary file `draft-release-notes-6.0.0.md`, and delete everything else (as already included in v5.3.0 release notes).

ACKs for top commit:
  furszy:
    ACK fbd0b9a
  Fuzzbawls:
    ACK fbd0b9a

Tree-SHA512: e95e1e1cd7f7948de306da67f45e527f35debeb71578dd3115f671a37bdfd8287e63608727ea833ebf221c4332610c836b3ff371a7be2b9b1696dc36313c7291

Author: Fuzzbawls