Edition endpoints: searchPeopleBy
This is similar to #46 and #47, but it should search people only in a particular course edition.
I thought this could go into edition endpoints, but I think it's also perfectly fine if it ends up going in `PersonController`.
### Endpoint (Method): searchPeopleByEditionAndUsernameContaining
<!-- An Endpoint allows a connecting service to make an HTTP call to LabraCORE -->
<!-- In this table, layout what information you want to get out of LabraCORE
and what information you expect to have to give LabraCORE -->
| Params | Type | Comment |
|--------|------|---------|
| Input | String | username |
| | Long | editionId |
| Output | `List<PersonViewDTO>` | people |
##### What does this method do?
<!-- Explain here, in however many steps needed, how you expect to go from
input to output. In many cases, this can just be a short explanation
of what you expect to come out. -->
1. Looking at what you guys did for the previous issues, I guess you'd do `findAllByUsernameContainingAndEditionsContaining`.
### Endpoint (Method): searchPeopleByEditionAndDisplayNameContaining
<!-- An Endpoint allows a connecting service to make an HTTP call to LabraCORE -->
<!-- In this table, layout what information you want to get out of LabraCORE
and what information you expect to have to give LabraCORE -->
| Params | Type | Comment |
|--------|------|---------|
| Input | String | displayName |
| | Long | editionId |
| Output | `List<PersonViewDTO>` | people |
##### What does this method do?
<!-- Explain here, in however many steps needed, how you expect to go from
input to output. In many cases, this can just be a short explanation
of what you expect to come out. -->
1. Looking at what you guys did for the previous issues, I guess you'd do `findAllByDisplayNameContainingAndEditionsContaining`.
### Endpoint (Method): searchPeopleByEditionAndNumberContaining
<!-- An Endpoint allows a connecting service to make an HTTP call to LabraCORE -->
<!-- In this table, layout what information you want to get out of LabraCORE
and what information you expect to have to give LabraCORE -->
| Params | Type | Comment |
|--------|------|---------|
| Input | Integer | number |
| | Long | editionId |
| Output | `List<PersonViewDTO>` | people |
##### What does this method do?
<!-- Explain here, in however many steps needed, how you expect to go from
input to output. In many cases, this can just be a short explanation
of what you expect to come out. -->
1. Looking at what you guys did for the previous issues, I guess you'd do `findAllByNumberStartingWithAndEditionsContaining`.
### Endpoint (Method): searchPeopleByEditionAndRole
<!-- An Endpoint allows a connecting service to make an HTTP call to LabraCORE -->
<!-- In this table, layout what information you want to get out of LabraCORE
and what information you expect to have to give LabraCORE -->
| Params | Type | Comment |
|--------|------|---------|
| Input | RoleType | role |
| | Long | editionId |
| Output | `List<PersonViewDTO>` | people |
##### What does this method do?
<!-- Explain here, in however many steps needed, how you expect to go from
input to output. In many cases, this can just be a short explanation
of what you expect to come out. -->
1. This should filter out people that have one particular role in a course edition. Is it possible to somehow get all roles in course edition (this already exists in `EditionController` as `getEditionParticipants`), then filter out one RoleType?
issue