Add checkboxes, checkbox groups and radio groups

[freya022]

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• I have checked the PRs for upcoming features/bug fixes.
• I have read the contributing guidelines.
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Changes

• Internal code
• Library interface (affecting end-user code)
• Documentation
• Other: _____

Closes Issue: NaN

Description

Add support for the new modal components.

These new components can allow your app to deliver a more polished UX for simple questions.

• Checkbox is for a simple yes or no
• RadioGroup allows the user to select one option out of multiple
• CheckboxGroup allows the user to select multiple options.

They all must be placed within Label components.

Changelogs: https://docs.discord.com/developers/change-log#radio-groups%2C-checkbox-groups%2C-and-checkboxes-in-modals
Docs PR: discord/discord-api-docs#8123

Example

Modal.create("modal-id", "Modal")
        .addComponents(
                Label.of("I like checking boxes", Checkbox.of("checkbox-id", true)),

                Label.of("Which Discord client do you use?", RadioGroup.create("radiogroup-id")
                                .addOption("Discord (Stable)", "stable", "The vanilla option", true)
                                .addOption("Discord PTB", "ptb", "A peek into the future")
                                .addOption("Discord Canary", "canary", "Living on the edge")
                                .build()),

                Label.of("Which modal components do you use?", CheckboxGroup.create("checkboxgroup-id")
                                .addOption("Text Inputs", "textinputs")
                                .addOption("Select Menus", "selectmenus")
                                .addOption("File Uploads", "fileuploads")
                                .addOption("Checkbox groups", "checkboxgroups", null, true)
                                .build()
                )
        )
        .build();