Make solana-ledger-tool run AccountsBackgroundService

[steviez]

Problem

Prior to this change, long running commands like solana-ledger-tool verify would OOM due to AccountsDb cleanup not happening.

Summary of Changes

Make solana-ledger-tool enable AccountsBackgroundService.

Credit to @mvines for doing most of the actual work in #26349.

Testing

I had previously been encountering an OOM after ~5k slots of processing on mnb with solana-ledger-tool on a ledger I had assembled for testing something else. With this change, I successfully processed the ~10k slots I had been hoping to without issue.

As an interesting perf datapoint, here is processing comparison between master and v1.10.32; the memory stats are taken from last print out immediately before last frozen bank:

# v1.10.32
datapoint: memory-stats total=269843996672i
  swap_total=1996796i
  free_percent=5.375635007967986
  used_bytes=83485450240i
  avail_percent=69.06158696519826
  buffers_percent=0.08825304210472022
  cached_percent=62.40292294391176
  swap_free_percent=98.64843479253764
...
ledger processed in 42 minutes, 27 seconds, 918 ms, 89 µs and 490 ns. root slot is 144172963, 34 banks: ...

# master
datapoint: memory-stats total=269843996672i
  swap_total=2044719104i
  free_percent=14.293261788173817
  used_bytes=19493175296i
  avail_percent=92.77613156623444
  buffers_percent=0.14457524377472322
  cached_percent=77.14281880468457
  swap_free_percent=98.49078223313748
...
ledger processed in 33 minutes, 3 seconds, 914 ms, 915 µs and 405 ns. root slot is 144172963, 34 banks: 1...

Fixes #26895

[mvines]

thanks for finishing off this work!

Pull request has been modified.