chore(engine): set scopeActivityInstance on HistoricVariableInstance

This commit adds a further column to the HistoricVariableInstanceEntity:
activityInstanceId. The "activityInstanceId" of a historic variable
instance expresses in which activity instance scope the variable is valid.

Furthermore, the commit adds some improvements:

- add variableInstanceId to historic details to be able to query after
  a log for a specific variable instance
- if the type of a variable will be changed an update of the variable
  happen (up to now the variable has been deleted and a new variable has
  been created instead of an simple update)
- add new columns to the correspoding tables
- update the upgrade scripts

related to CAM-73
chore(engine/rest): expose new query possibility to REST Api

Expose HistoricVariableInstanceQuery#activityInstanceIdIn() via REST Api

related to CAM-73
feat(engine/rest): expose HistoricDetailQuery via REST Api

related to CAM-73
chore(cockpit): set history from "audit" to "full"

... and add a process which changes variable instances.

related to CAM-73
fix(cockpit): change validation error message in variables tab
impr(engine/test): do not use JobExecutor to execute test cases