labplot2 rename

Description

Rename LabPlot2 to LabPlot. LabPlot1 never existed and the version number was always 2.x. When we switch to version 3.x we should leave the "2" behind.

TODO:

• .knsrc must be sysadmin reviewed
• https://cdn.kde.org/screenshots/labplot2
• .po translations
• flatpak: https://invent.kde.org/sysadmin/ci-utilities/-/blob/master/signing/flatpaksigner-projects.yaml
• snap?

Conformity

• Changelog entry

When external dependencies are removed

• Reporting to ...