Add missing modules to API docs

[mtrezza]

New Issue Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am not just asking a question.
• [x] I have searched through existing issues.
• [x] I can reproduce the issue with the latest version of the Parse Android SDK.
• [x] I can reproduce the issue with the latest version of Parse Server.

Issue Description

The API docs are missing some modules (FB, FCM, etc), they only contain the parse module.

Solution

Adapt API docs generation (javadoc) to include the missing modules in a single doc.

[mtrezza]

1188 partly solves this issue, but Kotlin sub-packages are still missing, see PR comment

[azlekov]

@mtrezza this SDK is published via Jitpack. Actually Jitpack supports multi-module javadoc - see here: https://jitpack.io/docs/#javadoc-publishing

[azlekov]

https://javadoc.jitpack.io/com/github/parse-community/Parse-SDK-Android/parse/1.26.0/javadoc/ - Showing parse module https://javadoc.jitpack.io/com/github/parse-community/Parse-SDK-Android/2.0.0/javadoc/ - Showing bolts module

[mtrezza]

This issue is already closed actually via #1118:

Forgot to link it, sorry.