Convert to general utilities

[mishankov]

Convert this application to general utilities application where string manipulation will be one of utilities. Other utilities may be:

• JSON/XML/YAML beautifier
• Converter (JSON - YAML - TOML - XML - CSV)
• Base64 (or BaseX) encode/decode
• File <-> Base64 converter
• URL encode/decode
• Datetime/unix time converter
• Change number base

Usage of some sort of code editor (CodeMirror, monaco, ...) may be useful

Lightweight Docker container for easy deployment

Desktop application

Maybe API to? Possibly separate builds for UI only tool and UI+API. Looks like it should be possible with SvelteKit