DPF: update the 25R2 changelog content

[PProfizi]

Hi everyone this PR produces the changelog for DPF 25R2.

Please do not hesitate to comment and propose changes.

You can view the file directly as rendered Mardkown here

[PProfizi]

Thanks @rafacanton, I've taken your comments about private PRs into account. I've also been over all features again to check whether they were related to public operators.
Concerning bug numbers and client names, yes they will definitely be removed. This list is the brute list of PRs with their numbers, used to retrieve descriptions by Antoine's tool.
Next I'll be going over fixes to attempt to better classify them and make sure they are related to public issues.

[rafacanton]

Minor things, but something got me thinking when I didn't see any fluid or LSDuna stuff... We are only tracking the DPF main repo! What about all the features developed in other repos (mainly lsdyna and plugins)? I guess this is a first and very nice changelog, but definitely something to include in the next cycle