feat: implement login/signup modal

[Rl0007]

Demo

oauth.flow.mp4

1. Dynamic Social Login Buttons (Populated based on Frappe's Social Login)
2. Bigger Login Modal
3. Social Login Buttons in Sign Up as well
4. Banner stays always
5. Removed banner animation as well.

Modal:

[NagariaHussain]

For the registration page, what we want is to refactor the flow. Right now, what happens is that if someone comes to the registration page and login is required, they are thrown to the login required component they have shown, and then the modal appears.

We want to do this instead, where they can view the registration form. This is just for the registration form, by the way, not the custom forms that we have done. Custom forms can still operate as they are doing.

In the registration page, they can see the form and do whatever they want. While checking out, if guest mode is not enabled, then the dialog appears that says "Log in to continue", and then it continues from there.

[NagariaHussain]

Check comment.

[Rl0007]

@NagariaHussain Yes, that's the plan. Basically we are replacing the redirection to /login with the "Login/Signup" modal that is global in context so if down the line we decide to use the same modal for custom forms we can do that as well. Thoughts?

[NagariaHussain]

The plan md does not have this flow refactor mentioned, hence pointed out. Yes, it should be a layout level component.

[Rl0007]

@NagariaHussain there is still one issue of forgot password it looks like this

Shall I create custom page for it in this PR or in a separate PR?

[NagariaHussain]

Let's do in a separate PR. Let's get this merged soon.