Remove Metadata length constraint and update dependencies

[jujaga]

Description

• The S3 spec only limits user metadata total header length to 2KB in size. It does not limit key nor value lengths to 255, so this PR lifts that constraint across the schema, model, and validation layers.
• Also performs routine npm dependency, base image and security updates

  SHOWCASE-3375

Types of changes

Bug fix (non-breaking change which fixes an issue)

Documentation (non-breaking change with enhancements to documentation) Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [x] I have read the CONTRIBUTING doc
• [x] I have checked that unit tests pass locally with my changes
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have added necessary documentation (if appropriate)

Further comments

[codeclimate[bot]]

Code Climate has analyzed commit 238b7088 and detected 3 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Duplication	3

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 64.7% (0.0% change).

View more on Code Climate.

[github-actions[bot]]

Coverage Report

Totals
Statements:	58.04% ( 2649 / 4564 )
Methods:	47.98% ( 297 / 619 )
Lines:	64.74% ( 1592 / 2459 )
Branches:	51.14% ( 760 / 1486 )