Normalize the salt caching API

https://github.com/saltstack/salt/pull/40429 changed the attribute used
in `salt/cache/__init__.py` without considering the usage of the cache
system elsewhere in the codebase. This led to a cascade of additional
changes to try to make everything work correctly.

This commit does 2 things:

1) Reverts the calls to the list function to use `list` instead of `ls`
   to conform with the established API used elsewhere in the codebase.

2) Modifies the cache modules so that they now use `list_` functions,
   aliased to `list` so that calls to cache loader instances' `*.list`
   functions elsewhere in the codebase will work.

salt/cache/__init__.py

@@ -224,7 +224,7 @@ class Cache(object):
         fun = '{0}.flush'.format(self.driver)
         return self.modules[fun](bank, key=key, **self._kwargs)
 
-    def ls(self, bank):
+    def list(self, bank):
         '''
         Lists entries stored in the specified bank.
 
@@ -240,11 +240,9 @@ class Cache(object):
             Raises an exception if cache driver detected an error accessing data
             in the cache backend (auth, permissions, etc).
         '''
-        fun = '{0}.ls'.format(self.driver)
+        fun = '{0}.list'.format(self.driver)
         return self.modules[fun](bank, **self._kwargs)
 
-    list = ls
-
     def contains(self, bank, key=None):
         '''
         Checks if the specified bank contains the specified key.

salt/cache/consul.py

@@ -61,7 +61,7 @@ api = None
 # Define the module's virtual name
 __virtualname__ = 'consul'
 
-__func_alias__ = {'list': 'ls'}
+__func_alias__ = {'list_': 'list'}
 
 
 def __virtual__():
@@ -139,7 +139,7 @@ def flush(bank, key=None):
         )
 
 
-def ls(bank):
+def list_(bank):
     '''
     Return an iterable object containing all entries stored in the specified bank.
     '''

salt/cache/localfs.py

@@ -23,7 +23,7 @@ import salt.utils.atomicfile
 
 log = logging.getLogger(__name__)
 
-__func_alias__ = {'list': 'ls'}
+__func_alias__ = {'list_': 'list'}
 
 
 def __cachedir(kwargs=None):
@@ -143,7 +143,7 @@ def flush(bank, key=None, cachedir=None):
     return True
 
 
-def ls(bank, cachedir):
+def list_(bank, cachedir):
     '''
     Return an iterable object containing all entries stored in the specified bank.
     '''

salt/cache/redis_cache.py

@@ -114,9 +114,7 @@ from salt.exceptions import SaltCacheError
 # -----------------------------------------------------------------------------
 
 __virtualname__ = 'redis'
-__func_alias__ = {
-    'ls': 'list'
-}
+__func_alias__ = {'list_': 'list'}
 
 log = logging.getLogger(__file__)
 
@@ -418,7 +416,7 @@ def flush(bank, key=None):
     return True
 
 
-def ls(bank):
+def list_(bank):
     '''
     Lists entries stored in the specified bank.
     '''