Make {N} project structure configurable

[sis0k0]

Currently, a {N} project has to follow a few conventions in order to be built with {N} CLI. For example, the source code should be in a folder named app, the application resources should be in app/App_Resources and so on.
The project structure should be configurable per project. For example, a project can have a .tns-cli.json file inside the project where the following can be specified:

• app folder name (currently 'app')
• app resources folder name
• folders/files to be included in the app and to be watched during livesync (related to Ability to ignore files from build and livesync #887)
  • This is particularly important when building apps with Angular 5. The package @angular/common contains localization files (~17Mb) which will get deployed on the device even if they are not used.

[dolanmiu]

Agreed.

I like to have my projects under src/app, just like how @angular/cli does it

[KristianDD]

Currently a file named "nsconfig.json" will be respected. The valid values inside it are as follows:

{
    "appPath": "test/src",
    "appResourcesPath": "resources"
}

Both paths must be relative to the project root(where the "package.json" file and "platforms" directory are located) in order everything to work as expected.

If appResourcesPath is omitted the CLI will assume that they are at their default location - folder called App_Resources inside the folder containing the rest of the app files.

If appPath is omitted CLI will assume the application files are located inside a folder called "app" inside the project folder.

Examples:
Lets say the project is located at "/d/work/myapplication".

1 "nsconfig.json" content:

{
    "appPath": "test/src"
}

Will result in app located at "/d/work/myapplication/test/src" and resources located at "/d/work/myapplication/test/src/App_Resources".

2 "nsconfig.json" content:

{
    "appResourcesPath": "resources"
}

Will result in app located at "/d/work/myapplication/app" and resources located at "/d/work/myapplication/resources".

3 "nsconfig.json" content:

{
    "appPath": "test/src",
    "appResourcesPath": "resources"
}

Will result in app located at "/d/work/myapplication/test/src" and resources located at "/d/work/myapplication/resources".

4 If no "nsconfig.json" file is present the app folder will be "/d/work/myapplication/app" and resources folder will be at "/d/work/myapplication/app/App_Resources"

The option folders/files to be included/excluded in the app and to be watched during livesync (related to #887) is still not implemented. Its discussion/implementation is moved in the separate issue.