Add Nexon Launcher

[MichaelHinrichs]

SteamDB app page links to a few games using this

• Mabinogi
• MapleStory
• Vindictus
• Dungeon Fighter Online
• Hyper Universe
• MapleStory 2

Brief explanation of the change

Find nxsteam.exe, the executable for Nexon Steam Game Launcher.

[SteamDB-Tracker]

After running changed rules in this pull request (this bot only tests rules.ini changes):

Changed technologies: Launcher.Nexon

These apps now match: (15) 212160 212200 212220 212240 216150 369200 442080 516080 560380 591530 861810 921940 927130 1232420 1711430

Please confirm that all these changed apps are correct.

[Lifeismana]

Missing non matching tests