starting support for remote.name.annexUrl set to annex+http

In this case, Remote.Git should not use that url for all access to
the repository. It will only be used for annex operations, which isn't
done yet.

P2P/Http/Url.hs

@@ -0,0 +1,18 @@
+{- P2P protocol over HTTP, urls
+ -
+ - Copyright 2024 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU AGPL version 3 or higher.
+ -}
+
+module P2P.Http.Url where
+
+import Data.List
+
+defaultP2PHttpProtocolPort :: Int
+defaultP2PHttpProtocolPort = 9417 -- Git protocol is 9418
+
+isP2PHttpProtocolUrl :: String -> Bool
+isP2PHttpProtocolUrl s = 
+	"annex+http://" `isPrefixOf` s ||
+	"annex+https://" `isPrefixOf` s