[Swift] Implements FlatbuffersVector which confirms to RandomAccessCollection (#8752)

* Implements FlatbuffersVector in swift

Implements FlatbuffersVector which confirms to RandomAccessCollection,
this would give us semi-native sugary syntax to all the arrays in swift port.

This work will also be the foundation of using arrays in swift

* Fix failing tests for Swift

swift/Sources/Common/padding.swift

@@ -23,7 +23,7 @@ import Foundation
 @inline(__always)
 public func padding(
   bufSize: UInt,
-  elementSize: UInt
-) -> UInt {
+  elementSize: UInt) -> UInt
+{
   ((~bufSize) &+ 1) & (elementSize &- 1)
 }