[meta] Blob storage usable by system and user applications

[ma2bd]

This generalizes and should ultimately replace bytecode storage.

• Add support for blobs in linera-storage::Storage #1982
• Create an operation PublishBlob that allows publishing a blob while a block is proposed #1991
• Create a GRPC entrypoint to download a blob #2028
• Create a GRPC entrypoint to download a certificate #2029
• Simplify chain info queries and always use separate GRPC queries to download blobs and certificates #2072
• Use hashes in requested_sent_certificates instead of full certificates.
• Create a GRPC entrypoint to request which certified block published or used a blob last in a given validator. #2030
• Support blob records in blocks (see oracle records) #2032
• Track the certified block that published or used a blob last #2033
• Use the new endpoint to make sure a client can always update a lagging validator about a blob it wants to use. #2151
• Create a system API read_blob #2073
• Upload the NFT's images as blobs and use them in the NFT example #2331
• Replace Bytecode by blobs #2149
• Require that BlockProposal contains exactly the published blobs. #2963
• Only the first read of a blob on any chain is considered an oracle call. #2964
• Disallow reading new blobs (oracle calls) on fast blocks. #2965
• Make the blob content a simple byte vector. #3050
• Support uploading blobs separately #3048
• Replace ApplicationDescription by blobs #2167
• Replace ChainDescription with blobs #2390
• Add resource policy for limiting the size of blobs #2186
• Support large blobs #2031
• Fees for publishing and reading blobs. #2172
• Only overwrite last_used_by if the new certificate is in a later epoch. #2271
• Executing a re-proposed block that uses an expired blob fails. #2993

Optional:

• DOS protection #2173
• Optimize requested_sent_certificate_hashes: If they are small, include full certificates. #2174
• Blob TTL #3051
• Explore the possibility of validators talking to each other and getting the blob they don't have #2187

Follow ups created from these:

• Don't hash on deserialization. #2136
• Consider explore having OracleRecord within linera-execution's OperationContext #2160
• Fix storage DOS attack in block proposals #2199
• Don't restart entire execution on client side when blobs are missing #2270
• Don't include blobs in chain info query responses #2301
• Move find_missing_confirmed_blobs_in_validator and maybe others into LocalValidatorNode #2302
• Merge test_finalize_validated into test_blob1, and the re_propose_validated tests with test_blob3 #2304
• Change blob bytes from Vec<u8> to Arc<[u8]> #2389
• Publish bytecode and create application in the same block #2547
• The pending blobs in the chain manager should be exactly the ones for the locked block. #2704
• The chain manager with blobs shouldn't be a single register view. #3013
• Convert proxy errors to NodeError #3033
• Create a test that exercises the Blob functionality. #3060