added gtts, make remove plugin dependencies from requirements, updated readme

bot/plugins/gtts_text_to_speech.py

@@ -0,0 +1,44 @@
+import datetime
+from typing import Dict
+
+from gtts import gTTS
+
+from .plugin import Plugin
+
+
+class GTTSTextToSpeech(Plugin):
+    """
+    A plugin to convert text to speech using Google Translate's Text to Speech API
+    """
+
+    def get_source_name(self) -> str:
+        return "gTTS"
+
+    def get_spec(self) -> [Dict]:
+        return [{
+            "name": "google_translate_text_to_speech",
+            "description": "Translate text to speech using Google Translate's Text to Speech API",
+            "parameters": {
+                "type": "object",
+                "properties": {
+                    "text": {"type": "string", "description": "The text to translate to speech"},
+                    "lang": {
+                        "type": "string", "description": "The language of the text to translate to speech."
+                                                         "Infer this from the language of the text.",
+                    },
+                },
+                "required": ["text", "lang"],
+            },
+        }]
+
+    async def execute(self, function_name, **kwargs) -> Dict:
+        tts = gTTS(kwargs['text'], lang=kwargs.get('lang', 'en'))
+        output = f'gtts_{datetime.datetime.now().timestamp()}.mp3'
+        tts.save(output)
+        return {
+            'direct_result': {
+                'kind': 'file',
+                'format': 'path',
+                'value': output
+            }
+        }