new command: bit start map="ui/card"

[qld-cf]

Description

Suggest:

1. my .bitmap already has many components, every time run bit start or hot-reload will take long long time;
2. so hope bit could support new command, like bit start map="ui/card" to run corresponding components
3. thanks, hope to get recover soon~

"ui/card": {
        "scope": "myscope.base-ui",
        "version": "0.0.18",
        "mainFile": "index.ts",
        "rootDir": "ui/card"
    },
"ui/xxxxxxxx": {
        "scope": "myscope.base-ui",
        "version": "0.0.11",
        "mainFile": "index.ts",
        "rootDir": "ui/xxxxxxxx"
    },
....