Move gacha files to separate directory and refactor file serving

[ghost]

Description

• Move gacha related files to separate directory
• Do not cache template HTML, allow for on-the-fly editing and updating without restarting server
• Check if account exists before trying to query player in gachaDetails
• Send proper HTTP codes when account/player/template not found
• Fix broken argument order for getGachaRecords
• Properly handle files as UTF-8
• Fix language mapping (record was completely broken since it was using en instead of en-us, while details was using improper casing [we seem to save locale as en-US in database but generated mappings are casted to lowercase])

Issues fixed by this PR

N/A

Type of changes

• Bug fix
• New feature
• Enhancement
• Documentation

Checklist:

• My code follows the style guidelines of this project
• My pull request is unique and no other pull requests have been opened for these changes
• I have read the Contributing note and Code of conduct
• I am responsible for any copyright issues with my code if it occurs in the future.

[mingjun97]

Fix language mapping (record was completely broken since it was using en instead of en-us, while details was using improper casing [we seem to save locale as en-US in database but generated mappings are casted to lowercase])

The en-us is given by certain anime game client actually. The when the in-game webview try to access web pages, it will give GET parameters like lang=[ISO639 language code]. The original implement was tyring to let the user decide which language they want to see.

[ghost]

The en-us is given by certain anime game client actually. The when the in-game webview try to access web pages, it will give GET parameters like lang=[ISO639 language code].

Was simply en for me :>