fix: add certificates to chart value

[susanshi]

Description

What this PR does / why we need it:

Update Ratify default helm chart to allow specification of akv cert Array
Quick start doc updated at https://github.com/deislabs/ratify-web/pull/33/files

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):

Fixes #1145

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Helm Chart Change (any edit/addition/update that is necessary for changes merged to the main branch)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

Covered by AKS e2e test. Please see test result at https://github.com/susanshi/ratify/actions/runs/6857271594

Post Merge Requirements

• MAINTAINERS: manually trigger the "Publish Package" workflow after merging any PR that indicates Helm Chart Change

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (29a38b6) 52.39% compared to head (b3b5b91) 52.39%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1172   +/-   ##
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  Coverage   52.39%   52.39%           
=======================================
  Files         101      101           
  Lines        6344     6344           
=======================================
  Hits         3324     3324           
  Misses       2699     2699           
  Partials      321      321           

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