Rename all plugin command configs to .dist

[tsautier]

Problem

Command configuration files (core.conf, sitebot.conf, etc.) were distributed as .conf files directly. When users upgraded DrFTPD, their custom configurations were overwritten by the new default files.

Solution

Rename all command config files to .conf.dist and update the config loader to use .dist files as fallback when the user's .conf file doesn't exist.

Changes Made

1. Renamed Config Files (All Plugins)

All command config files in src/main/resources/master/config/commands/{ftp,irc}/ were renamed to .conf.dist:

• core.conf, sitebot.conf, archive.conf, autonuke.conf, dupecheck.conf, find.conf, imdb.conf, jobs.conf, mirror.conf, request.conf, speedtest.net.conf, tvmaze.conf, zipscript.conf

2. Updated Config Loader

Modified GlobalContext.loadCommandConfig() to:

1. Search for both .conf AND .conf.dist files
2. For each .conf.dist file, check if the corresponding .conf exists
3. Only load .conf.dist if .conf is missing (user config takes priority)

Upgrade Behavior

Scenario	What Happens
Fresh install	.conf.dist is loaded (user has no .conf)
User has custom .conf	User's .conf is loaded, .conf.dist ignored
Upgrade	Only .conf.dist is updated, user's .conf untouched

Fixes: #244

[tsautier]

@mvangoor @hrxcodes for review