Add support for multiple operations

[PvtPuddles]

I would like the GraphQL plugin to support having multiple operations in a single scratch file.

For example, I may have a file that looks like this:

query getUser ($id: Int!) {
    user(id: $userId) {
        id, name
    }
}

mutation updateUser ($id: Int!, $newName: String!){
    updateUser(id: $userId, name: $newName)
}

Ideally, I would like a run button in the gutter for each operation in the file.

Additionally, I would like a dropdown menu when I click the existing run button to select the desired operation, similar to the GraphQL Playground on the web.

[PvtPuddles]

I didn't realize that the query is selected according to where your mouse cursor is.

I will close the issue.