Improve LiveDataDock and import widget
Summary:
- settings are only applied to the element selected first in the project explorer
- add name (editable) and source (read-only) line edit
- optimize access to MQTT host data (reduce QMap searches)
- disable/enable reading type options for different source types
- distinguish MQTT source by host name and port
- allow different LiveDataSources from the same host
Test Plan:
- create new LiveData sources (Ascii, ROOT, MQTT)
- select several of them in the project explorer, but edit only one
- change name in dock widget
Reviewers: LabPlot, asemke
Reviewed By: LabPlot, asemke
Subscribers: sgerlach, asemke, kde-edu
Tags: KDE Edu
Differential Revision: https://phabricator.kde.org/D18319