Move inputs from ETS to disk

[bchamagne]

Description

Once a UTXO is spent, we move it to disk to reduce memory footprint.

Fixes #624

Type of change

• New feature

How Has This Been Tested?

This is tested in the integration tests.
I did not do any BEFORE/AFTER metrics, should I do some benchmark?

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[bchamagne]

IMPORTANT NOTE: we loose millisecond precision due to serialization using DateTime.to_unix/1

[samuelmanzanera]

Thanks for the PR, I wrote you some comments to improve it in terms of performances and maintainability.

[samuelmanzanera]

IMPORTANT NOTE: we loose millisecond precision due to serialization using DateTime.to_unix/1

If we would like to preserve it, we can use DateTime.to_unix(date, :millisecond)

[samuelmanzanera]

After restart of the node, the inputs are duplicated with different state

To reproduce it, start a node, do 2 faucet requests, stop the node, and restart it. Then go to the previous addresses generated, you will see the double inputs, one spent and one unspent, while they are the same.

[bchamagne]

After restart of the node, the inputs are duplicated with different state

To reproduce it, start a node, do 2 faucet requests, stop the node, and restart it. Then go to the previous addresses generated, you will see the double inputs, one spent and one unspent, while they are the same.

This happened because the transactions history was processed in inverse-chronological order. Resulting in spend_all_transactions(previous_address) not doing anything because the previous was not existing yet in memloader. To fix the issue, we reversed the processing of transactions history to be chronological.