RFR: 8223375: Remove Netbeans specific files from the source code repository

[Kevin Rushforth]

As discussed in [this message](https://mail.openjdk.java.net/pipermail/openjfx-dev/2020-July/027049.html) on
openjfx-dev I propose to remove the old netbeans-specific files from the source repository. They were originally done
for NetBeans 8 / FX 8,. They sort of worked (but not well) with FX 9 (still using NB 8), but no longer work at all. The
gradle support in the latest Apache NetBeans 12 is already pretty good, with a couple bugs that they need to fix. There
is no longer a reason to host these old netbeans project files in our repo.

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Commit messages:
 - 8223375: Remove Netbeans specific files from the source code repository

Changes: https://git.openjdk.java.net/jfx/pull/302/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=302&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8223375
  Stats: 32535 lines in 155 files changed: 0 ins; 32535 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/302.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/302/head:pull/302

PR: https://git.openjdk.java.net/jfx/pull/302