Introduce BridgeJS, a declarative JS interop system

[kateinoigakukun]

#290
This is very early stage of the development but enough to ship as MVP.

See examples and documentations for more details:

• Examples/ImportTS
• Examples/ExportSwift
• Article: Exporting Swift to JavaScript
• Article: Importing TypeScript into Swift
• Article: Ahead-of-Time Code Generation with BridgeJS
• Build pipeline overview

[github-actions]

Time Change: +300ms (2%)

Total Time: 10,125ms

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import	26ms	+3ms (9%)	🔍
Serialization/Swift Int to JavaScript with assignment	350ms	+19ms (5%)	🔍
Serialization/JavaScript Number to Swift Int	278ms	+17ms (6%)	🔍
Serialization/Swift String to JavaScript with call	1,121ms	+61ms (5%)	🔍

View Unchanged

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import with int	21ms	-1ms
Serialization/JavaScript function call from Swift	129ms	-1ms
Serialization/Swift Int to JavaScript with call	1,013ms	+30ms (2%)
Serialization/Swift String to JavaScript with assignment	430ms	+19ms (4%)
Serialization/JavaScript String to Swift String	3,908ms	+150ms (3%)
Object heap/Increment and decrement RC	2,809ms	-1ms (0%)

View Baselines

Test name	Duration
Serialization/Call JavaScript function directly	10ms
Serialization/Assign JavaScript number directly	8ms
Serialization/Call with JavaScript number directly	7ms
Serialization/Write JavaScript string directly	8ms
Serialization/Call with JavaScript string directly	7ms

[kateinoigakukun]

Merging behind a feature flag