Move GraphEditor from examples to jbotsim-extras-swing

[remikey]

The GraphEditor is currently in the examples section. We consider moving it to jbotsim-extras-swing module.

GraphEditor feature

It provides a way to interactively import/create/export (in tikz) a Topology. The user can use the integrated JConsole as a way to interact with the created Topology.

Remark

The current code is a bit buggy and would require some refactoring. For example, JConsole could be moved from jbotsim-core to jbotsim-extras-swing module.

[remikey]

Note: JConsole and GraphEditor have been removed from the source tree before the 1.0.0 release. See https://github.com/jbotsim/JBotSim/commit/a1e94be575397c6cfac2d94461ba18c962fd863c .