Feature/api create user show endpoint

I tried to rebase on dev and was unable to:

```
c7ab071 Added some properties to the API user representer
db5b99e Added API show user endpoint
021a673 Added links and embedded resources to the work package API resource
31bd77d Got rid of some inline WP properties
5168470 Got rid of authorization for show user API endpoint
828adb5 Added API show user endpoint
fad50e2 Added links and embedded resources to the work package API resource
f8619af Just moved some stuff around
1a3b2a9 Added API show user endpoint
d491a6c Added links and embedded resources to the work package API resource
cac8acc Got rid of authorization for show user API endpoint
bc753c8 Added links and embedded resources to the work package API resource
b164ac6 Just moved some stuff around
aa7e84a Corrected some errors in API work package representer
2aa42e6 Show assignee & responsible in the WP detail overview
dbc8681 Added some properties to the API user representer
c234e23 Added API show user endpoint
4c5562e Added links and embedded resources to the work package API resource
d0e92a7 Got rid of some inline WP properties
0845090 Got rid of authorization for show user API endpoint
26a75af Added links and embedded resources to the work package API resource
ab00b91 Just moved some stuff around
a65d015 Added some properties to the API user representer
a382548 Added API show user endpoint
e33f0bd Added links and embedded resources to the work package API resource
a15a47e Got rid of some inline WP properties
b7a51da Got rid of authorization for show user API endpoint
950c7fe Added some properties to the API user representer
cf30f52 Added API show user endpoint
6ec5e42 Added links and embedded resources to the work package API resource
1850976 Added some properties to the API user representer
29f1acf Got rid of some inline WP properties
e3a98c5 Got rid of authorization for show user API endpoint
b355721 Just moved some stuff around
4e5b974 Corrected some errors in API work package representer
5b0a821 Show assignee & responsible in the WP detail overview
```