Update project dependencies

[paulapreuss]

OpenPlan is currently based on python 3.9, which has already reached it's EoL, and Django 4.2, which has its long term support (LTS) phase also ending at the end of the year. Additionally, most project dependencies have not been updated in a long time, posing possible security issues, among other things.

This PR aims to upgrade the project to python 3.12 and Django 5.2 (as a compromise between a jump to all latest versions and moving to versions that have at least two years of long term support ahead). Other project dependencies will also be checked for upgrades.

Within this PR, oemof packages are also upgraded to oemof-solph==0.5.7 and oemof-thermal==0.0.8. Will have to do some testing. Likely these versions were pinned to be in sync with MVS, but since we are moving away from MVS we will need to update anyway. The upgrade was necessary, since the package dependencies were not compatible with python 3.12.

Closes #399

TODO:

• Check and potentially update security settings
• Update README
• Update local deploy settings / instructions

[Bachibouzouk]

I just though yesterday that we were due to update django. Shouldn't we unpin the dependencies ? I would keep a file with pinned dependencies but use the one with unpinned such that we always get the latest updates when we deploy (we could setup a scheduled job to build using the unpinned requirements and be notifyed when it fails). If it fails and it is a friday or one day before a workshop and one has no time, we can fallback on the pinned dependencies and leave it as TODO to fix the dependencies later.

[Bachibouzouk]

We don't need exchangelib anymore :)

[Bachibouzouk]

We don't need oemof-solph if I am not mistaken, we will need oemof-datapackage as I updated in #422 and this will install solph