[Config] Ajv: support the option allErrors

[LoicPoullain]

Issue

Resolves #633

Solution and steps

• Add the option.

Checklist

• Add/update/check docs (code comments and docs/ folder).
• Add/update/check tests.
• Update/check the cli generators.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (v1-7-0@09e5f82). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             v1-7-0     #642   +/-   ##
=========================================
  Coverage          ?   99.62%           
=========================================
  Files             ?       90           
  Lines             ?     1590           
  Branches          ?      336           
=========================================
  Hits              ?     1584           
  Misses            ?        6           
  Partials          ?        0

Impacted Files	Coverage Δ
packages/core/src/common/utils/get-ajv-instance.ts	100% <ø> (ø)

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