[2p2c][2pnc][2pncmin] Update phase presence indices and formulation indices -> identical to 2pnc
2p2c updated the reference solutions (changed phase presence indices) 2pnc changed: plSg --> pnsw; pgSl --> pwsn, removed plSg + pgSl from indices 2pncmin changed: plSg --> pnsw; pgSl --> pwsn as for 2pnc 2p2c, 2pnc: added the formulation changes to CHANGELOG.md
edit for next branch: Added the changes also to the 2pnc privarswitch
(cherry picked from commit b03738a2)