remove unused files

These were ported to SignalMessaging

Signal/src/util/NSString+OWS.m

@@ -1,26 +0,0 @@
-//
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
-//
-
-#import "NSString+OWS.h"
-#import "UIView+OWS.h"
-
-NS_ASSUME_NONNULL_BEGIN
-
-@implementation NSString (OWS)
-
-- (NSString *)rtlSafeAppend:(NSString *)string referenceView:(UIView *)referenceView
-{
-    OWSAssert(string);
-    OWSAssert(referenceView);
-
-    if ([referenceView isRTL]) {
-        return [string stringByAppendingString:self];
-    } else {
-        return [self stringByAppendingString:string];
-    }
-}
-
-@end
-
-NS_ASSUME_NONNULL_END