Proposed schedule for JavaFX 17

[Kevin Rushforth]

  Here is the proposed schedule for JavaFX 17.

RDP1: Jul 8, 2021 (aka “feature freeze”)
RDP2: Jul 29, 2021
Freeze: Aug 19, 2021
GA: Sep 7, 2021

We plan to fork a jfx16 stabilization branch at RDP1. The GA date is 
expected to be one week ahead of JDK 17, matching what we did for 16.

As was done for the previous release, the start of RDP1, the start of 
RDP2, and the code freeze will be 16:00 UTC on the respective dates.

Please let Johan or me know if you have any questions.

-- Kevin