chore(backup): serialize the backup header [WPB-10575]

[vitorhugods]

WPB-10575 Cross Platform Backup: Write common backup / restore library

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PR Submission Checklist for internal contributors

• The PR Title

  • conforms to the style of semantic commits messages¹ supported in Wire's Github Workflow²
  • contains a reference JIRA issue number like SQPIT-764
  • answers the question: If merged, this PR will: ... ³

• The PR Description

  • is free of optional paragraphs and you have filled the relevant parts to the best of your ability

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What's new in this PR?

Issues

We need to be able to read and write the actual backup file, which contains metadata in its start.

Solutions

1. Define a BackupHeader format (documented in the README).
2. Write a Serializer that is able to convert a Header into a bytearray, and vice-versa.

In a future PR, this serializer + encryption (developed in another PR) will be joined together by an entity responsible for creating and restoring backups.

Testing

Test Coverage

• I have added automated test to this contribution

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PR Post Merge Checklist for internal contributors

• If any soft of configuration variable was introduced by this PR, it has been added to the relevant documents and the CI jobs have been updated.

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References

1. https://sparkbox.com/foundry/semantic_commit_messages
2. https://github.com/wireapp/.github#usage
3. E.g. feat(conversation-list): Sort conversations by most emojis in the title #SQPIT-764.

[github-actions]

Test Results

3 359 tests   3 252 ✅  5m 29s ⏱️
  572 suites    107 💤
  572 files        0 ❌

Results for commit e8e1a5c.

♻️ This comment has been updated with latest results.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (epic/multiplatform-backup@77f183f). Learn more about missing BASE report.

Additional details and impacted files

@@                     Coverage Diff                      @@
##             epic/multiplatform-backup    #3159   +/-   ##
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  Coverage                             ?   54.03%           
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  Files                                ?     1246           
  Lines                                ?    36152           
  Branches                             ?     3656           
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  Hits                                 ?    19534           
  Misses                               ?    15208           
  Partials                             ?     1410           

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[datadog-wireapp]

Datadog Report

Branch report: backup/chore/read-write-backup-header
Commit report: fd0d3ad
Test service: kalium-jvm

✅ 0 Failed, 3252 Passed, 107 Skipped, 37.33s Total Time

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud