feat: w3filecoin spec with storefront aggregator broker and chain rol…

…es (#71)

Based on my previous proposal to @Gozala that @Gozala covered in
storacha/RFC#2

Changes the aggregation spec introducing new capabilities and a new
role. Main reasoning for this change is the new distinction between
Storefront and Aggregator (previously had same identity), where a
Storefront (web3.storage, nftstorage) will receive/compute Filecoin
pieces (from received CAR files) and offer them to an Aggregator
(w3filecoin). The aggregator's role is to put multiple pieces together
to offer a large piece (aggregate) to a Broker (spade-proxy).

Per the above, the new invocations added are described in
https://www.notion.so/2023-07-26-aggregation-protocol-contract-sign-and-report-API-12b4a7f0e92f4b789c331322e2629817

Renamed spec from aggregation to w3 filecoin given the context increased
from aggregation to accommodate new requirements

Note that `list`, will be added later on

---------

Co-authored-by: Irakli Gozalishvili <[email protected]>

.github/workflows/words-to-ignore.txt

@@ -110,3 +110,11 @@ Fil
 Ucanto
 ucanto
 natively
+storageAggregatorPrincipal
+w3filecoinDealerPrincipal
+SpadeChain
+SpadeChainPrincipal
+TrackerPrincipal
+16GiB
+NOP
+deduplicated