Add GetConfirmedBlocksWithLimit RPC method

[mvines]

GetConfirmedBlocks requires that I provide an end_slot or else I get fed up to 500,000 blocks. This is wasteful when I just want to poke around the ledger and return a block or two after a given slot (eg, the first block in an epoch).

To get around this add GetConfirmedBlocksWithLimit, which requires a starting slot and a limit.

Adding a new method seemed conceptually much simpler than trying to shoehorn an optional limit argument at the end of GetConfirmedBlocks. Also GetConfirmedBlocks still has it's uses (ie, when I want to fetch all confirmed blocks in a given epoch) so it deserves to continue to exist as a non-deprecated method alongside GetConfirmedBlocksWithLimit

[codecov]

Codecov Report

Merging #12599 into master will increase coverage by 0.0%.
The diff coverage is 87.8%.

@@           Coverage Diff           @@
##           master   #12599   +/-   ##
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  Coverage    82.1%    82.1%           
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  Files         358      358           
  Lines       83580    83650   +70     
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+ Hits        68630    68698   +68     
- Misses      14950    14952    +2     

[mvines]

@CriesofCarrots - wdyt?

[CriesofCarrots]

Wfm, I will definitely make use of it! The request_processor method internals could be deduped, but they are simple enough that it feels like more trouble than it's worth.

[mvines]

The request_processor method internals could be deduped, but they are simple enough that it feels like more trouble than it's worth.

My thinking as well, not worth the trouble.