Add user customized menu id mid

[huanhe4096]

Users can add a mid to each menu item to identify which menu item is clicked/touched.

For example, in the HelloWorld.vue

menu: [
  { mid: "new_file", name: "New File", iconSlot: "file" },
  { mid: "new_win", name: "New Window", iconSlot: "window" },
  { mid: "open_file", name: "Open File", iconSlot: "folderopen" },
]

When handleSelected event, the mid is included in the return object:

const handleSelected = (item) => {
    console.log(item);
};

When clicking "New File", it will show { pmid: "new_file", name: "New File", path: ...}.

I hope this can be helpful to address issue #61 and #62

[prabhuignoto]

@huanhe4096 thanks for opening the PR. just curious why we need a special mid attribute. which menu item is clicked/touched can be detected even without that

[huanhe4096]

@huanhe4096 thanks for opening the PR. just curious why we need a special mid attribute. which menu item is clicked/touched can be detected even without that

Hello @prabhuignoto ! For most of time, I think the existing attributes are good enough. The need for mid in our case is that our PM often change the menu name and structure ... for example, move "File>Settings" to "Edit>Preferences", or move "Help>About us" to "Icon>About" ... so we want to keep this appearance changing away from the actual function implementation, although it's not a big change.