Resolve ambiguity with apprise.plugins module namespace

While the namespace is physically made of modules, it has been amended
to be the namespace home for the corresponding notifier classes as well.

This turned out to confuse both humans and machines on various ends.

While it has apparently worked for a while, it croaks on Python 3.11
now, and is not considered to have been a good idea in general.

test/test_plugin_prowl.py

@@ -26,9 +26,8 @@ from unittest import mock
 
 import pytest
 import requests
-from apprise.plugins.NotifyProwl import ProwlPriority
-from apprise import plugins
 import apprise
+from apprise.plugins.NotifyProwl import NotifyProwl, ProwlPriority
 from helpers import AppriseURLTester
 
 # Disable logging for a cleaner testing output
@@ -50,7 +49,7 @@ apprise_url_tests = (
     }),
     # Provider Key
     ('prowl://%s/%s' % ('a' * 40, 'b' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
     }),
     # Invalid Provider Key
     ('prowl://%s/%s' % ('a' * 40, 'b' * 20), {
@@ -58,58 +57,58 @@ apprise_url_tests = (
     }),
     # APIkey; no device
     ('prowl://%s' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
     }),
     # API Key
     ('prowl://%s' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
         # don't include an image by default
         'include_image': False,
     }),
     # API Key + priority setting
     ('prowl://%s?priority=high' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
     }),
     # API Key + invalid priority setting
     ('prowl://%s?priority=invalid' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
     }),
     # API Key + priority setting (empty)
     ('prowl://%s?priority=' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
     }),
     # API Key + No Provider Key (empty)
     ('prowl://%s///' % ('w' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
 
         # Our expected url(privacy=True) startswith() response:
         'privacy_url': 'prowl://w...w/',
     }),
     # API Key + Provider Key
     ('prowl://%s/%s' % ('a' * 40, 'b' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
 
         # Our expected url(privacy=True) startswith() response:
         'privacy_url': 'prowl://a...a/b...b',
     }),
     # API Key + with image
     ('prowl://%s' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
     }),
     ('prowl://%s' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
         # force a failure
         'response': False,
         'requests_response_code': requests.codes.internal_server_error,
     }),
     ('prowl://%s' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
         # throw a bizzare code forcing us to fail to look it up
         'response': False,
         'requests_response_code': 999,
     }),
     ('prowl://%s' % ('a' * 40), {
-        'instance': plugins.NotifyProwl,
+        'instance': NotifyProwl,
         # Throws a series of connection and transfer exceptions when this flag
         # is set and tests that we gracfully handle them
         'test_requests_exceptions': True,
@@ -134,16 +133,16 @@ def test_plugin_prowl_edge_cases():
     """
     # Initializes the plugin with an invalid apikey
     with pytest.raises(TypeError):
-        plugins.NotifyProwl(apikey=None)
+        NotifyProwl(apikey=None)
     # Whitespace also acts as an invalid apikey value
     with pytest.raises(TypeError):
-        plugins.NotifyProwl(apikey='  ')
+        NotifyProwl(apikey='  ')
 
     # Whitespace also acts as an invalid provider key
     with pytest.raises(TypeError):
-        plugins.NotifyProwl(apikey='abcd', providerkey=object())
+        NotifyProwl(apikey='abcd', providerkey=object())
     with pytest.raises(TypeError):
-        plugins.NotifyProwl(apikey='abcd', providerkey='  ')
+        NotifyProwl(apikey='abcd', providerkey='  ')
 
 
 @mock.patch('requests.post')
@@ -175,7 +174,7 @@ def test_plugin_prowl_config_files(mock_post):
     """ % ('a' * 40, 'b' * 40)
 
     # Disable Throttling to speed testing
-    plugins.NotifyProwl.request_rate_per_sec = 0
+    NotifyProwl.request_rate_per_sec = 0
 
     # Prepare Mock
     mock_post.return_value = requests.Request()