EIP-4844: Shard Blob Transactions (ethereum#4844)

* Shard Blob Transactions

* EIP-4844: implement review suggestions from Micah

* EIP-4844: update (pre-)draft EIP comparisons to not introduce dependencies, describe instead

* EIP-4844: list required tx type EIP requirements

* EIP-4844: formatting review fixes by @lightclient

Co-authored-by: lightclient <14004106+lightclient@users.noreply.github.com>

* EIP-4844: clarifications by @djrtwo

Co-authored-by: Danny Ryan <dannyjryan@gmail.com>

* EIP-4844: clarify blobs downloading requirement, define is_data_available

* Update EIPS/eip-4844.md

Co-authored-by: lightclient <14004106+lightclient@users.noreply.github.com>
Co-authored-by: Danny Ryan <dannyjryan@gmail.com>
Co-authored-by: Micah Zoltu <micah@zoltu.net>