feat: unique table column validator

[vesse]

Added unique validator for table column. Usage:

  validators:
    - unique: true
      column: UNIQUE_COL

What's maybe missing:

• documentation updates
• should the validator check existing values when updating to a newer recipe version?

[majori]

should the validator check existing values when updating to a newer recipe version?

Yeah, the predefined values are checked here:

jalapeno/pkg/recipeutil/values.go

Line 72 in 50235f6

for i := range targetedVariable.Validators {