feat: refactoring and extending the support of validation property assignments

[iifawzi]

PR Checklist

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• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

Only a limited number of decorators are supported, and are listed directly in the model-class visitor.
Issue Number: N/A

What is the new behavior?

1- Extended it to support the following decorators:

• Contains
• ArrayNotEmpty
• ArrayUnique
• ArrayMaxSize
• ArrayMinSize
• IsDivisibleBy
• IsEmail
• IsMobilePhone
• IsJSON
• IsUrl
• IsUuid
• IsBase64
• IsCreditCard
• IsCurrency
• IsAscii
• IsHexColor
• IsHexadecimal,

2- After adding these decorators the file became too long and hard to read, that's why I thought of refactoring it to separate the concerns and isolate the facts ( decorators to properties mappings ) so it's not flooding the visitor, and easier to read and maintain.

If you think this refactor is unnecessary or anything could be improved, let me know.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[iifawzi]

Hi, are there any updates on this?

[kamilmysliwiec]

LGTM