Add availableOn[Client,Server] options

[tarmolov]

Rename existing method:
.hideOnDocPage -> .setOption('hiddenOnDocPage', true)

Add two new options:
.setOption('availableOnClient', false);
.setOption('availableOnServer', false);

If both options availableOnClient and availableOnServer are set to false, the error should be thrown.

//cc @dodev

[dodev]

You mean, if both options are set to 'false'.
Otherwise, LGTM 👍

[tarmolov]

Yeap. Fixed :)

[tarmolov]

Final changes:

• Delete the method hideOnDocPage(). Now you should use setOption('hiddenOnDocPage', true).
• Add option executeOnServerOnly to prevent execution on frontend side. I picked this name because only one option has been added.

Methods with set option have a special badge:

And the middleware returns a following error:

{
    type: "BAD_REQUEST",
    message: "Method can be executed only on server side"
}

I didn't add option executeOnClientOnly because the middleware executes all methods on the server side. If I set executeOnClientOnly option to true for a method, the middleware cannot execute this method. Of course I could add a special option to api.exec method but it would look as a hack and I didn't like it.