Include view for User Defined Functions (UDFs)

With 4.5.0 UDFs became available in all versions. Right now one has to know where to look for existing UDFs defined in the `information_schema.routines` table like so:

```sql
SELECT
routine_schema,
routine_name,
specific_name,
data_type,
routine_definition,
routine_body
FROM information_schema.routines
where routine_body = 'javascript';
```

**Feature description**
- Integrate a view in the AdminUI similar to the ones for SQL views, listing all available UDFs (definition, input and output data types) and a convenient way to replace an existing UDF
- **Optional**: List usage of UDFs in tables / views (e.g. generated columns)