Additional custom document validation

[davelopez]

The current validation of the tool documents is based on the Galaxy XML Schema Definition.
There are some validation rules that are interesting to have to better comply with the IUC best practices that do not necessarily need to be enforced by the schema definition (see galaxyproject/galaxy#11196) but would be great to display them as warnings during tool wrapper development.
For example:

• The id attribute of a tool should be lowercase and contain only letters, numbers, underscores, and dashes. If a tool declares an id that does not follow this pattern a warning should be displayed.
• Show warning when multiple macro definitions share the same name.