debug, eth: define error when accessing pruned chain data

[lightclient]

This adds an error in the RPC when a users requests data that has been pruned.

Affected RPC:

• eth_getBlockByHash
• eth_getBlockByNumber
• eth_getBlockTransactionCountByHash
• eth_getBlockTransactionCountByNumber
• eth_getUncleCountByBlockHash
• eth_getUncleCountByBlockNumber
• eth_getBlockReceipts
• eth_getTransactionByBlockHashAndIndex
• eth_getTransactionByBlockNumberAndIndex
• eth_getTransactionReceipt

It would be better to create a reusable error for this, but that will require reorganzing the project structure, updating the build pipeline, and resolving the site generation issues. I started working on this here, but wasn't able to get the site generator working. We need to just move to docausauraus.

[MarekM25]

I like it, LGTM

[s1na]

It should be the same for debug_getRawBlock and debug_getRawReceipts.

[s1na]

There is an open question on eth_getLogs: if the range goes beyond the cutoff point, do we return an error or only return logs for post-cutoff point? I am thinking the latter but want to raise it in case others disagree.

[fjl]

We think it should be like this: if the starting point of a getLogs query is before the defined history cutoff point on a pruned node, the query should be rejected. It's incorrect to return partial logs.