✔ Geosite group validation + PAC regeneration on version update

[database64128]

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Description of your pull request and other information

• Validate geosite group configuration
• Reset to default if specified group doesn't exist
• Regenerate pac.txt on version update (can be turned off)
• Cleanup of Configuration to separate loading logic and processing logic

[chenshaoju]

There is an tiny odd issue in Shadowsocks-4.2.0.40-Release.exe, when I override update from 4.2.1.0, The Edit Servers window shows up when Shadowsocks startup.

After re-open Shadowsocks 2 times, the Edit servers window does not show up in startup again. 🤔

[chenshaoju]

👍 Looks good to me, but someone else must approve.

[database64128]

There is an tiny odd issue in Shadowsocks-4.2.0.40-Release.exe, when I override update from 4.2.1.0, The Edit Servers window shows up when Shadowsocks startup.

After re-open Shadowsocks 2 times, the Edit servers window does not show up in startup again. 🤔

That's because I changed the variable name from isDefault to firstRun for clarification. The old value is not migrated to the new one. So the program thinks it's the first run. 😅