Set max open rocksdb files to 8192

[vicsn]

Motivation

rocksdb is creating and leaving open hundreds of files. While at the moment this is harmless, if it keeps growing in the future it could cause nodes to halt.
It is unknown what will happen once the max system-wide limit is hit.
To prevent that from happening, this PR sets a conservative limit.

Test Plan

Has been tested on a mainnet client. lsof outputs imply the node stayed below the limits anyway:

• Initial values: 120k total snarkos file descriptors, 1047 unique
• After a restart: 110k total snarkos file descriptors, 1049 unique
• After a restart with this PR: 20k total snarkos file descriptors, 159 unique
• After a resync with this PR: 80k total snarkos file descriptors, 781 unique

[onetrickwolf]

@vicsn should be able to test this today at some point.

[vicsn]

@onetrickwolf amazing. Apologies one more extended question: at the end, with this new version, could you also remove the client's ledger, let it resync, and share the resulting lsof file after its finished syncing? Resyncing might trigger the creation of the file descriptors faster.

[onetrickwolf]

@vicsn yeah sure this will probably be a day or two until we are fully synced though.

[zkxuerb]

LGTM

[vicsn]

@vicsn yeah sure this will probably be a day or two until we are fully synced though.

Note to reviewers: test ran succesfully. It seems the node stayed far below this set limit anyway, so its not urgent, but useful defense in depth. I added data in the PR description above.