Incompatible with KNIME version 4

[sverhoeven]

A major release of KNIME Analytics Platform, version 4, is about to be released.

The 3D-e-Chem KNIME nodes have their KNIME dependencies pinned to >=3.X.0 and <4.0.0 and the nodes use KNIME v3 p2 update sites.

The child plugins must be made KNIME 4 compatible first:

• [x] pharmacophore
• [x] gpcrdb
• [x] modifiedtanimoto
• [x] sstea
• [x] kripodb
• [x] sygma
• [x] molviewer
• [x] klifs
• [x] silicosit
• [x] plants
• [x] python
• [x] plugin