Have a list of constants for supported character sets for password generation recipe

[edif2008]

Summary

Currently, when making a password recipe, you need to specify the character sets that can be used when generating the password (e.g. SYMBOLS, LETTERS, DIGITS). However, it can be tricky to know by heart the supported character sets.

Also, it would be nice to have a sort of validation of the recipe before sending the request to Connect. As a starting inspiration, you can check the validRecipe function from Node SDK.

Tasks to be done

• Add a new type that will be used as a field purpose, along with the constants that represent the supported character sets. Add this in onepassword/items/go. Please ensure that all constants are set by checking out this part of the Connect API documentation
  Note: Feel free to change the name of the type, as well as the constant names. This is just a sample code of what it can look like.

  type CharacterSets string
  
  const (
      Letters CharacterSets = "LETTERS"
      Symbols CharacterSets = "SYMBOLS"
      Digits  CharacterSets = "DIGITS"
  )

• Change the CharacterSets property of the GeneratorRecipe struct to use the new type. (line 132)

  // GeneratorRecipe Representation of a "recipe" used to generate a field
  type GeneratorRecipe struct {
      Length            int             `json:"length,omitempty"`
      CharacterSets     []CharacterSets `json:"characterSets,omitempty"`
      ExcludeCharacters string          `json:"excludeCharacters,omitempty"`
  }

• If needed, add a validator function that validates the provided list of character sets. If this is added, also add tests that make sure the validator works as expected.