fix: use memory friendly file split logic

[daniel-s-palmer]

Description

When splitting a tarball using --max-package-size, zarf will load the entire tarball into memory and copy it to new slices before writing the new files to disk resulting in memory usage up to 2x of the tarball. This can result in large memory usage when the package tarball is large itself.

This PR updates the logic to read the original tarball in chunks of 16 MiB at a time thereby fixing the memory issue.

Testing

Will be breaking this down into a few sections:

1. Test setup
2. Test off of main
3. Test off of PR

Test setup

We will be reusing the TestMultiPartPackage test and updating src\test\packages\05-multi-part\zarf.yaml to the following to test a larger package size and setting --max-package-size=500:

kind: ZarfPackageConfig
metadata:
  name: multi-part
components:
  - name: big-ol-file
    required: true
    description: test larger package around 2GB
    images:
      - atlassian/confluence-server:8.6.0-jdk17
      - atlassian/confluence-server:8.5.1-jdk17

We will expect the test to fail as the number of expected split files will no longer match the original test, however we will be able to see the memory usage while the test runs.

We will capture memory usage using top | grep zarf.

Test off of main

Before we look at the results from the code changes, lets first look at the results from main for comparison.

zarf-2024-01-27-23-31-37-3566031216.log

When the package tarball is being split, memory tops out at 2.1g

Test off of PR

zarf-2024-01-27-23-42-37-480658840.log

When the package tarball is being split, memory remains steady at under 250m

Related Issue

Fixes #2231

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed

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[Racer159]

Sorry for the delay, one tiny change on the messaging but should be GTG after that

[Racer159]

lgtm