RFR: JDK-8303443: IGV: Syntax highlighting and resizing for filter editor [v2]

[Tobias Holenstein]

> In the Filter window of the IdealGraphVisualizer (IGV) the user can double-click on a filter to edit the javascript code. 
> 
> - Previously, the code window was not resizable and had no syntax highlighting
> <img width="782" alt="editor_old" src="https://user-images.githubusercontent.com/71546117/222137737-1042b272-2c4f-4ae2-929d-2c5d285818e4.png">
> 
> - Now, the code window can be resized by the user and has basic syntax highlighting for `keywords`, `strings` and `comments`
> <img width="727" alt="editor_new" src="https://user-images.githubusercontent.com/71546117/222137687-892ba36d-4a76-4769-ada7-7982ea59a5ac.png">

Tobias Holenstein has updated the pull request incrementally with four additional commits since the last revision:

 - revert .js ending for filters
 - copyright year
 - form working in Netbeans IDE
 - Monospaced font

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/12803/files
  - new: https://git.openjdk.org/jdk/pull/12803/files/34169439..4b2dd4a5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12803&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12803&range=00-01

  Stats: 18 lines in 3 files changed: 5 ins; 6 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/12803.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12803/head:pull/12803

PR: https://git.openjdk.org/jdk/pull/12803