[DMN Designer] Select Box for Decision Table input columns

Currently the decision table input columns can be named with any name. However their names should correspond to InputData elements in the DRG, thus we should provide select box for each decision table input column, where user would select corresponding InputData element for the given decision table input column.

Acceptance test

1. Sorting in select box
2. Rename InputData, change reflected in select box
3. Same InputData connected to multiple nodes, appropriate select boxes contain the value