Update SDK readme with native authentication content

[Dickson-Mwendia]

This PR updates the readme to include the native authentication capabilities for MSAL Android.

For the documentation updates and links:

• We point to the official MSAL Android docs on MS Learn - https://learn.microsoft.com/en-us/entra/msal/android

• Within the getting started section of the readme, we provide links to the different quickstarts/tutorials that devs can follow, based on their scenario and type of app they're building (workforce/customer)

• I've also removed much of the content that's duplicated in the official docs (configuration, initialize client app, and acquire tokens) and instead pointed to the guidance on MS Learn, i.e:

  • Official MSAL Android documentation on how to instantiate your client application and acquire tokens.

As for the code samples, we also need to differentiate the between workforce and customer sample apps, that's why we have two links. Eventually, the links will point to the code samples browser, such as (https://learn.microsoft.com/en-us/samples/browse/?products=microsoft-authentication-library) I'm working to get all code samples for Android onboarded there.

[iamgusain]

Let's add some description to the PR explaining what we are changing here and why.

[Dickson-Mwendia]

@negoe @iamgusain could you please have another look at this?

[Dickson-Mwendia]

Thanks @negoe . I've updated the section that introduces native auth. Please have a look. Also, let me know what you think about renaming the H2 "Native authentication support in MSAL" and if this could bring more clarity to our customers.