Uninstalling tableview plugins leads to webclient not initializing if tableviews topics exist

Steps to reproduce:

• Install dmx-tableview
• Start DMX Webclient + Create Tableviews
• Uninstall dmx-tableview
• Reload DMX Webclient

Tested with latest DMX 5.1-SNAPSHOT (today).

After tableview removal the webcient crashes during initialization with the following error:

0c7c98530d4c45e1ddaa.main.js:29 Rendering topicmap 3789 failed Error: unknown topicmap type 'dmx.tableview'
    at 0c7c98530d4c45e1ddaa.main.js:29
    at 0c7c98530d4c45e1ddaa.main.js:29
    at new Promise (<anonymous>)
    at h (0c7c98530d4c45e1ddaa.main.js:29)
    at u.showTopicmap (0c7c98530d4c45e1ddaa.main.js:29)
    at Array.<anonymous> (0c7c98530d4c45e1ddaa.main.js:7)
    at u.dispatch (0c7c98530d4c45e1ddaa.main.js:13)
    at dispatch (0c7c98530d4c45e1ddaa.main.js:7)
    at 0c7c98530d4c45e1ddaa.main.js:29

This may be not limited to tableview but might also the case after the removal of any plugin providing a custom maptype extension and maps of that maptype exist.

Proposed solution: The webclient should be more robust towards that case and boot-up nonetheless.