support bitswap configurability (#8268)

* feat: extract Bitswap fx initialization to its own file
* chore: bump go-bitswap dependency
* feat: bump go-ipfs-config dependency and utilize the new Internal.Bitswap configuration options. Add documentation around the new OptionalInteger config type as well as the Internal.Bitswap options.
* docs(docs/config.md): move the table of contents towards the top of the document and update it

Co-authored-by: Petar Maymounkov <petarm@gmail.com>
Co-authored-by: Marcin Rataj <lidel@lidel.org>
Co-authored-by: Gus Eggert <877588+guseggert@users.noreply.github.com>