Remove pylint no-self-use and its disable directives

It's been moved to optional checker and we won't activate it. Was not
really useful and switching to static methods in all places would
carry other interesting problems and no positives as shown in: pylint-dev/pylint#5502

.pylint.rc

@@ -65,7 +65,6 @@ enable=
     bad-except-order,
     redefined-builtin,
     unused-variable,
-    no-self-use,
     import-self,
     useless-object-inheritance,
     unused-argument,

rotkehlchen/api/rest.py

@@ -3978,7 +3978,6 @@ def perform_assets_updates(
         )
 
     def get_all_binance_pairs(self, location: Location) -> Response:
-        # pylint: disable=no-self-use
         try:
             pairs = list(query_binance_exchange_pairs(location=location).keys())
         except InputError as e:
@@ -4005,12 +4004,12 @@ def get_user_binance_pairs(self, name: str, location: Location) -> Response:
             status_code=HTTPStatus.OK,
         )
 
-    def add_manual_price(  # pylint: disable=no-self-use
-        self,
-        from_asset: Asset,
-        to_asset: Asset,
-        price: Price,
-        timestamp: Timestamp,
+    def add_manual_price(
+            self,
+            from_asset: Asset,
+            to_asset: Asset,
+            price: Price,
+            timestamp: Timestamp,
     ) -> Response:
         historical_price = HistoricalPrice(
             from_asset=from_asset,
@@ -4027,12 +4026,12 @@ def add_manual_price(  # pylint: disable=no-self-use
             status_code=HTTPStatus.CONFLICT,
         )
 
-    def edit_manual_price(  # pylint: disable=no-self-use
-        self,
-        from_asset: Asset,
-        to_asset: Asset,
-        price: Price,
-        timestamp: Timestamp,
+    def edit_manual_price(
+            self,
+            from_asset: Asset,
+            to_asset: Asset,
+            price: Price,
+            timestamp: Timestamp,
     ) -> Response:
         historical_price = HistoricalPrice(
             from_asset=from_asset,
@@ -4049,21 +4048,21 @@ def edit_manual_price(  # pylint: disable=no-self-use
             status_code=HTTPStatus.CONFLICT,
         )
 
-    def get_manual_prices(  # pylint: disable=no-self-use
-        self,
-        from_asset: Optional[Asset],
-        to_asset: Optional[Asset],
+    def get_manual_prices(
+            self,
+            from_asset: Optional[Asset],
+            to_asset: Optional[Asset],
     ) -> Response:
         return api_response(
             _wrap_in_ok_result(GlobalDBHandler().get_manual_prices(from_asset, to_asset)),
             status_code=HTTPStatus.OK,
         )
 
-    def delete_manual_price(  # pylint: disable=no-self-use
-        self,
-        from_asset: Asset,
-        to_asset: Asset,
-        timestamp: Timestamp,
+    def delete_manual_price(
+            self,
+            from_asset: Asset,
+            to_asset: Asset,
+            timestamp: Timestamp,
     ) -> Response:
         deleted = GlobalDBHandler().delete_manual_price(from_asset, to_asset, timestamp)
         if deleted: