Extend check for variables/tasks/roles names

[CarstenGrohmann]

Currently var_naming_pattern provides a general pattern how variables names should looks like. A similar pattern in hard coded for role names. But it's missing for task names.

Black list options don't exists for all three element types.

We discussed our coding guidelines in my team and decided not to use variables with:

• ^data$ or ^result$(too unspecific)
• tmp (we want to use temp only)
• current resp. cur (unspecific since we are migrating data from source to target)

Please think about:

• adding an option like var_naming_pattern for tasks
• adding three options to check variables/tasks/roles names for unwanted pattern
• adding an option like "var_name_prefix" e.g. to enforce variable names with role name as prefix

Thanks,
Carsten