Theia: add a command to theia cli to trim unnecessary files

[akosyakov]

See discussions here: https://github.com/theia-ide/theia-apps/pull/94#issuecomment-433863851

[uniibu]

I don't know much about using lerna in particular, but correct me if im wrong, i think adding this to lerna.json

...
"commands": {
    "publish": {
      "ignore": [
        "*.md",
        "*.ts",
       "*.ts.map",
        "*.txt",
        "test/**"
        ... etc
      ]
    }
}
...

would prevent lerna from publishing those unnecessary files.

Or ofcourse if .npmignore works normally with lerna then those unnecessary files could be listed there.

[akosyakov]

We want to publish them for extension developers that they can have a look at source code and example usages. Only developers building prod applications should use this command.

[uniibu]

To further discuss, i think adding a command to cli might not work. Because doing yarn --production will remove cli as devdependency, and if you do it before doing yarn --production, it will add back those files.

I think adding option on build would be nice, something like yarn theia build --production which would remove unnecessary files and devdependencies.