lnwire+channeldb+pool: extend the reader/write buffer pools to cover channeldb+lnwire #3004
Description
Today we use a set of read/write buffer pools to reduce the amount of allocation that occurs doing routine operation. This tends us to a steady state of allocations, and reduce heap pressure as well. These buffer pool are used in the brontide package and the peer when reading/writing messages of the wire. We can also use these pools within channeldb when serializing and decoding message, and also within lnwire when decoding message. Once these two areas are covered, most allocations due to encoding/decoding will no go through these buffer pools. During the development process, we may want to re-examine the default number of workers for these buffer pools.