Bug fixes

[ReneSchroederLJ]

Description

• fixed an error in retrieving the correct list of partners when creating a delivery
• added missing mandatory field indicators
• changed the naming of "Supplier Site" to "Expected Supplier Site" in the add demand modal
• fixed translation of weekdays to english language

resolves #417, #421, #429, #523, #798, #799

Pre-review checks

Please ensure to do as many of the following checks as possible, before asking for committer review:

• DEPENDENCIES are up-to-date. Dash license tool. Committers can open IP issues for restricted libs.
• Copyright and license header are present on all affected files
• If helm chart has been changed, the chart version has been bumped to either next major, minor or patch level (compared to released chart).

[tom-rm-meyer-ISST]

LGTM, when walking through your fixes, I noticed that the #798 was a duplicate of #421