Update/simplify npm scripts

[jonaro00]

Proposed changes

• The project flag in the lint script caused it to not find linting violations. After the change, it warns for == and var etc. Also added src.compiler to that command.
• Removed redundant project flags on generate scripts.
• Simplified C#/Kt build scripts.

Checklist

• I consent that this change becomes part of alphaTab under it's current or any future open source license
• Changes are implemented
• Existing builds tests pass

Further details

• This is a breaking change
• This change will require update of the documentation/website