- [X] Adds `ToSpan()` for SpanWriter.
- [X] Moves house files to UOContent/Multis/Houses
- [X] Adds house packets
### SpanWriter.ToSpan()
`ToSpan()` returns an `SpanOwner` struct which allows access to the buffer as a Span by calling `Span`.
Example:
```cs
public SpanOwner CreatePacket()
{
var writer = new SpanWriter(0x400);
// write some stuff
return writer.ToSpan();
}
```
In this example, we are creating a packet and returning the `SpanOwner` for caching. This means in the future we can do something like this:
```cs
ns.Send(_cachedPacket.Span);
```
Where `_cachedPacket` is the `SpanOwner`
Notes:
Do not use a SpanWriter, or attempt to dispose of it after calling `ToSpan()`. Doing so will probably cause an NPE.
- [X] Converts boat packets
- [X] Makes a packet container builder for packet 0xF7
- [X] Generalizes world item packet so it works for mobiles too
Notes:
- This PR doesn't address proper smooth movement for boats.
