FEATURE REQUEST: Revamp the way packets are being written to a more standalone approach

[Tofaa2]

Is your feature request related to a problem? Please describe.
PacketEvents currently has no way to write buffer content besides the PacketWrapper class, which limits the usage to specifically packets only.

Describe the solution you'd like
We could make a standalone class that is responsible for reading and writing from a ByteBuf, rather than bundling every single method inside the PacketWrapper class.

Basic approach brainstorm: https://hastebin.com/share/emaqogenel.java

[Tofaa2]

#860