Separation of application and user data

Currently, appNG employs the following directory layout:

ROOT
├── applications
├── debug
├── META-INF
├── repository
├── uploads
└── WEB-INF
    ├── bin
    ├── cache
    ├── classes
    ├── conf
    ├── lib
    ├── log
    └── repository

Application data and user data are mixed. To be able to update appNG more easily, a new environment variable APPNG_DATA should be defined, pointing to the directory which contains instance specific user and configuration data.

Following directories should be relocated to APPNG_DATA:

ROOT
├── applications
├── debug
├── repository
├── uploads
└── WEB-INF
    ├── conf
    └── log

The location of ROOT/WEB-INF/repository is already configurable. It would be nice if this folder would also be located below APPNG_DATA by default and would be called app-repository. ROOT/repository would be called site-repository in the future.

In APPNG_DATA the WEB-INF folder is not required, i.e. the directory layout below APPNG_DATA would be flat:

APPNG_DATA
├── applications
├── app-repository
├── conf
├── debug
├── log
├── site-repository
└── uploads

Following directories will be retained in the webapps-folder:

ROOT
├── META-INF
└── WEB-INF
    ├── bin
    ├── cache
    ├── classes
    └── lib

This makes upgrading appNG very easy: Just replace the contents of the ROOT-folder with the files of the new appNG version.