split ProvidedInfo and UserProvidedInfo

The latter is for git-annex matchexpression and matching against it can
throw an exception. Splitting out the former reduces the potential for
mistakes and avoids needing to worry about matching against that
throwing an exception.

This is more groundwork for matching largefiles while importing,
without downloading content.

This commit was sponsored by Graham Spencer on Patreon.

Annex/Import.hs

@@ -541,15 +541,12 @@ wantImport :: FileMatcher Annex -> ImportLocation -> ByteSize -> Annex Bool
 wantImport matcher loc sz = checkMatcher' matcher mi mempty
   where
 	mi = MatchingInfo $ ProvidedInfo
-		{ providedFilePath = Right $ fromRawFilePath $ fromImportLocation loc
-		, providedKey = unavail "key"
-		, providedFileSize = Right sz
-		, providedMimeType = unavail "mime"
-		, providedMimeEncoding = unavail "mime"
+		{ providedFilePath = fromImportLocation loc
+		, providedKey = Nothing
+		, providedFileSize = sz
+		, providedMimeType = Nothing
+		, providedMimeEncoding = Nothing
 		}
-	-- This should never run, as long as the FileMatcher was generated
-	-- using the preferredContentKeylessTokens.
-	unavail v = Left $ error $ "Internal error: unavailable " ++ v
 
 {- If a file is not preferred content, but it was previously exported or
  - imported to the remote, not importing it would result in a remote