refactoring REST interface API

with the first implementation the idea was to have the following kind of scheme:

```
GET /api/management/profiles/ to have the list of all profiles
GET /api/management/profiles/<pk> to have a specific profile
```

the problem that arises is that to have a list of positions/projects or other information for a specific profile, two solutions were possible:

1. put everything in the response when querying /api/management/profiles/&lt;pk&gt;
2. have a longer url to fetch only specific eg positions for a profile (/api/management/profiles/positions/&lt;pk&gt;) with the primary key of the profile at the end of the url. 

However when we will need to update information of a position for a profile, we will have the following kind of pattern:

```
/api/management/profiles/positions/<person>/<position>
```

That becomes a little bit ugly and the intend is not necessarly clear. So, I create a branch for two reasons:

1. use plain python function in place of methodview subclass that limit a little bit the kind of url that we can build (more information has to be taken  - to be confirmed)
2. have a better url scheme. 

For the same example as over, I would like to have something as follow:

```
/api/management/profiles/<person>/positions/<position>
```

and to continue for the project:

```
/api/management/profiles/<person>/positions/<position>
```