[DMN Designer] Data-types: Clean-up

During review of the PRs adding support to the different grids, both jomarko@redhat.com and karreiro_ found some re-occurring issues that need addressing. Rather than fix at the point of discovery, i.e. when my colleagues review the PR, I prefer to circle back and fix all together once the queue of pending PRs are merged.

Current action items:

• https://github.com/kiegroup/kie-wb-common/pull/2055#discussion_r212084447

• https://github.com/kiegroup/kie-wb-common/pull/2041#discussion_r212250221

• https://github.com/kiegroup/kie-wb-common/pull/2075/files#diff-5192d74da9265134c5792e63362222faR202 and https://github.com/kiegroup/kie-wb-common/pull/2075/files#diff-5192d74da9265134c5792e63362222faR206 - check for other occurrences too. If we pass a parameter as to whether to update "Stunner" title or not we can remove these methods accessing the super implementation.

• Review whether legacy BaseExpressionGrid.HeaderTextAreaFactory related methods are required when all grids support "in place" editing of name and data-type. Removing if possible.

Acceptance test

Data type can be changed for

• All supported node types
• All supported expression types