Fix integer min/max range schema validation

[bobanm]

What was the problem?

This PR resolves #8617

How was it solved?

• Updated definition of uint32 and uint64 formats to include required type: 'number' property
• Removed definitions of int32 and int64 formats, as they are already included in the default AJV formats
• Added 10 new test cases
• BONUS 1: Simplified how Lisk Validator loads custom formats 😎
• BONUS 2: Simplified how schemas are defined in lisk_validator_formats test suite 😎

How was it tested?

All tests passing 👌🏻

[codecov]

Codecov Report

Merging #8743 (0f27a40) into release/6.0.0 (0f27a40) will not change coverage.
The diff coverage is n/a.

❗ Current head 0f27a40 differs from pull request most recent head 1b9e96f. Consider uploading reports for the commit 1b9e96f to get more accurate results

Additional details and impacted files

@@              Coverage Diff               @@
##           release/6.0.0    #8743   +/-   ##
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  Coverage          83.30%   83.30%           
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  Files                593      593           
  Lines              22294    22294           
  Branches            3292     3292           
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  Hits               18573    18573           
  Misses              3721     3721