Add index for TASK_ID on ACT_HI_OP_LOG table

AT:

• the following index is added for all sql scrips:
  • create index ACT_IDX_HI_OP_LOG_TASK on ACT_HI_OP_LOG( TASK_ID_);
• the sql update scripts are adjusted accordingly

So that:

• querying by TASK_ID_ in ACT_HI_OP_LOG table does not end up in full table scan