Add SSZ missing containers

[Arkenan]

In order to have more complete spec tests, we need to add the missing SSZ containers:

• Eth1Block
• SyncAggregatorSelectionData
• ContributionAndProof
• SignedContributionAndProof
• SyncCommitteeContribution
• SyncCommitteeMessage

Low priority:

• LightClientBootstrap
• LightClientFinality
• LightClientHeader
• LightClientOptimisticUpdate
• LightClientUpdate
• PowBlock