Add Projects to manage groups of resources

As discussed in class we would like a way to create projects where bikes and users can be allocated. This is how we discussed the data structure could look like.

```javascript
projects: {
image: Image,
name: String,
startDate: Date,
endDate: Date,
// Place to pickup and dropoff bikes (only one place to keep it simple)
address: {
streetName: String,
streetNumber: String,
city: String,
areaCode: String,
country: String
},
users: {},
bikes: {},
restrictions: {
// Min and max duration to be allowed to book a bike
duration: {
minDays: Int,
maxDays: Int
},
// Times for pickup and dropoff (opening hours)
times: [
{
begin: Date,
end: Date
},
{
begin: Date,
end: Date
}
],
schema: {

},
// Is it allowed to extend ones booking
extend: {
allowed: Bool,
minAmount: Int,
maxAmount: Int
}
}
}
```

The issue gives a proposed project data structure but names no implementation files or tests. Start by reviewing the repository's database abstraction and existing resource models, then clarify the project scope and relationships before implementing. Done should include project creation and management with the specified bikes, users, address, dates, and restrictions.

Written by the indexing model from the issue text.