Remove PHP abstractions, http, authentication and serialization packages

[Ndiritu]

New Kiota PHP repos:

• https://github.com/microsoft/kiota-abstractions-php
• https://github.com/microsoft/kiota-http-guzzle-php
• https://github.com/microsoft/kiota-authentication-phpleague-php
• https://github.com/microsoft/kiota-serialization-json-php
• https://github.com/microsoft/kiota-serialization-text-php

[baywet]

Can you also update the section readmes like this one please? https://github.com/microsoft/kiota/blob/main/abstractions/README.md

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

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