Feature - Support for organizations

**Describe the solution you'd like**
Support for organizations and not just users. Requires a different GraphQL call, but it is doable.
Requires a different prop when using the component, and therefore we risk that neither name nor organization is added, so adequate testing is needed.

**Additional context**

It should be very similar to existing call, except user is switched out with organization.
```
query someQuery($org: String!, $numRepositories: Int!, $numCommits: Int!) {
organization(login: $org){
repositories(first: $numRepositories, orderBy: {field: UPDATED_AT, direction: DESC}) {
...
```

Start by locating the existing user GraphQL call and the component prop that supplies the user, then compare it with the organization(login: $org) query shown here. Done means the component supports organizations as well as users and tests cover both inputs, including the case where neither name nor organization is provided.

索引モデルが issue の本文から書いたものです。