[Core] add [p]set api list and [p]set api remove (#4370)

* add get_shared_api_keys

* add set listapi command

* fix typo

* refactor `[p]set listapi` into `[p]set api list`

* remove unnecessary check

* fix decorators

* corrected wording

* add remove_shared_api_services

* add `set api remove`

* further typo sniping

* bugsniping

* minor typo

* aaaaaaaaa

* Apply suggestions from code review

Co-authored-by: Draper <27962761+Drapersniper@users.noreply.github.com>

* update api docstring to reflect new subcommands

* Apply suggestions from code review

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* update framework_apikeys.rst with new methods

* Update redbot/core/bot.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* rewrite get_shared_api_services into a special case of
get_shared_api_tokens

* rewrite api_list to include keys and tokens in response

* don't show secrets

* better api_remove response

* black

* remove nonexistent method

* remove unnecessary import

* fix wording

* Improve docstrings and type hints

- added overloads to help out developers a bit more
  * this wasn't necessary, but development tools work better
    with this information
- fixed type hint to use Union as now
  its return type depends on whether `service_name` is passed
- updated docstrings to contain information about the added behavior

* Use `humanize_list()` rather than `str.join()`

This is done for consistency within Red
and it makes the list have the last element joined
with `and` (or its equivalent in chosen locale)

* Use `.format()` after translation is applied

If `.format()` is used before `_()`, the search for translation is done
with the string that already has the dynamic text added,
which results in no matches.

* Add plural support

* Improve error message

Updated message to be more specific
(used phrases: "None of the services" and "had any keys set")
and a bit more nice to the user (judging word "anyway" removed)

* Improve readability of `[p]set api list`

It's a lot clearer when the sublists are indented,
especially on mobile where code blocks aren't colored at all.

New look:
https://user-images.githubusercontent.com/6032823/94614944-3bbd7c80-02a7-11eb-89e4-64bdf06c650b.png

Co-authored-by: Draper <27962761+Drapersniper@users.noreply.github.com>
Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

redbot/core/bot.py

@@ -26,6 +26,7 @@ from typing import (
     Any,
     Literal,
     MutableMapping,
+    overload,
 )
 from types import MappingProxyType
 
@@ -986,22 +987,37 @@ class RedBase(
         """
         return await self._config.guild(discord.Object(id=guild_id)).mod_role()
 
-    async def get_shared_api_tokens(self, service_name: str) -> Dict[str, str]:
+    @overload
+    async def get_shared_api_tokens(self, service_name: str = ...) -> Dict[str, str]:
+        ...
+
+    @overload
+    async def get_shared_api_tokens(self, service_name: None = ...) -> Dict[str, Dict[str, str]]:
+        ...
+
+    async def get_shared_api_tokens(
+        self, service_name: Optional[str] = None
+    ) -> Union[Dict[str, Dict[str, str]], Dict[str, str]]:
         """
-        Gets the shared API tokens for a service
+        Gets the shared API tokens for a service, or all of them if no argument specified.
 
         Parameters
         ----------
-        service_name: str
-            The service to get tokens for.
+        service_name: str, optional
+            The service to get tokens for. Leave empty to get tokens for all services.
 
         Returns
         -------
-        Dict[str, str]
+        Dict[str, Dict[str, str]] or Dict[str, str]
             A Mapping of token names to tokens.
             This mapping exists because some services have multiple tokens.
+            If ``service_name`` is `None`, this method will return
+            a mapping with mappings for all services.
         """
-        return await self._config.custom(SHARED_API_TOKENS, service_name).all()
+        if service_name is None:
+            return await self._config.custom(SHARED_API_TOKENS).all()
+        else:
+            return await self._config.custom(SHARED_API_TOKENS, service_name).all()
 
     async def set_shared_api_tokens(self, service_name: str, **tokens: str):
         """
@@ -1051,6 +1067,25 @@ class RedBase(
             for name in token_names:
                 group.pop(name, None)
 
+    async def remove_shared_api_services(self, *service_names: str):
+        """
+        Removes shared API services, as well as keys and tokens associated with them.
+
+        Parameters
+        ----------
+        *service_names: str
+            The services to remove.
+
+        Examples
+        ----------
+        Removing the youtube service
+
+        >>> await ctx.bot.remove_shared_api_services("youtube")
+        """
+        async with self._config.custom(SHARED_API_TOKENS).all() as group:
+            for service in service_names:
+                group.pop(service, None)
+
     async def get_context(self, message, *, cls=commands.Context):
         return await super().get_context(message, cls=cls)