Update custom Doclet configuration for javadoc (#587)
Update custom Doclet configuration for javadoc (#587)

* Update custom Doclet configuration for javadoc

From version 3.0 and up `javadoc` has updated parameter names used in custom Doclet configurations, which affects our internal devsite scripts.
This PR updates the config to use the new parameters names.

* Update other param instances

* remove java 8 exception

* Add -Xdoclint:none option

* Added <doclint>none</doclint>
firebase/firebase-admin-java,firebase/firebase-admin-java