More privatization, and some error helpers (#2976)

* More privatization, and some error helpers

This makes a lot more things private. Continued from #2967, fixes #2984
Adds public methods for various things.

Below is a brief summary of things available elsewhere, though this
particular set of changes may warrant a detailed section in the release notes.

 - bot.db.locale -> redbot.core.i18n.get_locale
   - Note: This one already existed.
 - bot.db.help -> redbot.core.commands.help.HelpSettings
 - bot db whitelist/blaclist? -> bot.allowed_by_whitelist_blacklist
   - This has also been made a single cannonical function for this
   purpose including check usage
 - bot color? -> bot.get_embed_color/bot.get_embed_colour
 - bot.id.api_tokens? ->

   - bot.get_shared_api_tokens
   - bot.set_shared_api_tokens
   - bot.remove_shared_api_tokens

 -bot.db.prefix -> bot.get_valid_prefixes
   - (Note: This is a wrapper around bot.get_prefix)

 Other changes include
  - removing `bot.counter` as it was never used anywhere
  - Adding properties with helpful error messages for moved and renamed
  things
  - making bot.uptime a property with an error on set
  - adding a migration to the bot config for shared_api_tokens

* Remove overly encompassing message redaction, eval is a risk, dont run in dev if you cant manage it

* address Flame's feedback

* rephrase example

* changelog extras

* You saw nothing

redbot/core/global_checks.py

@@ -4,34 +4,8 @@ from . import commands
 
 def init_global_checks(bot):
     @bot.check_once
-    async def global_perms(ctx):
-        """Check the user is/isn't globally whitelisted/blacklisted."""
-        if await bot.is_owner(ctx.author):
-            return True
-
-        whitelist = await bot._config.whitelist()
-        if whitelist:
-            return ctx.author.id in whitelist
-
-        return ctx.author.id not in await bot._config.blacklist()
-
-    @bot.check_once
-    async def local_perms(ctx: commands.Context):
-        """Check the user is/isn't locally whitelisted/blacklisted."""
-        if await bot.is_owner(ctx.author):
-            return True
-        elif ctx.guild is None:
-            return True
-        guild_settings = bot._config.guild(ctx.guild)
-        local_blacklist = await guild_settings.blacklist()
-        local_whitelist = await guild_settings.whitelist()
-
-        _ids = [r.id for r in ctx.author.roles if not r.is_default()]
-        _ids.append(ctx.author.id)
-        if local_whitelist:
-            return any(i in local_whitelist for i in _ids)
-
-        return not any(i in local_blacklist for i in _ids)
+    async def whiteblacklist_checks(ctx):
+        return await ctx.bot.allowed_by_whitelist_blacklist(ctx.author)
 
     @bot.check_once
     async def bots(ctx):