Resolve "Migration guide pyotb 1.5.4 --> 2.0.0"

Closes #104 (closed)

I took the liberty to add OTBObject.summarize() for backward compatibility purpose, and also convenience (this way the API is more flexible). However I am open to discuss its non-return, not a big deal.

Basically this MR consists in new decorators (in deprecated.py) for the depreciation of methods, arguments, and the otbObject class. Flashy color warning appear to suggest user to replace arguments names, when it's backward compatible, and exception are thrown (DepreciationWarning) when it's not. I have brought back the App.__getattr__ only to throw a DepreciationWarning explaining how to migrate, when the App.app attribute exists.

Maybe I have missed a few old attributes. With the decorators we can add them for depreciation easily.

to do

• add warnings and depreciation decorators in code
• write a note on migration in documentation

pyotb/core.py

@@ -430,34 +430,30 @@ class OTBObject(ABC):
             "`App.app` can be used to call otbApplications methods. "
         )
 
-        if item[0].isupper():
+        if item in dir(self.app):
             # Because otbApplication instances methods names start with an
             # upper case
             note += (
                 f"Maybe try `pyotb_app.app.{item}` instead of "
                 f"`pyotb_app.{item}`? "
             )
+            if item.startswith("GetParameter"):
+                note += (
+                    "Note: `pyotb_app.app.GetParameterValue('paramname')` can be "
+                    "shorten with `pyotb_app['paramname']` to access parameters "
+                    "values."
+                )
 
-        if item[0].islower():
+        elif item in self.parameters_keys:
             # Because in pyotb 1.5.4, applications outputs were added as
             # attributes of the instance
             note += (
                 "Note: `pyotb_app.paramname` is no longer supported. Starting "
-                "from pytob 2.0.0, `pyotb_app['paramname']` can be used to "
+                "from pyotb 2.0.0, `pyotb_app['paramname']` can be used to "
                 "access parameters values. "
             )
-
-        if item.startswith("GetParameter"):
-            note += (
-                "Note: `pyotb_app.app.GetParameterValue('paramname')` can be "
-                "shorten with `pyotb_app['paramname']` to access parameters "
-                "values."
-            )
         depreciation_warning(note)
-        raise AttributeError
-
-
-
+        raise AttributeError(f"'{type(self)}' object has no attribute '{item}'")
 
     def __getitem__(self, key) -> Any | list[float] | float | Slicer:
         """Override the default __getitem__ behaviour.