Add `@Consume(content-type)` to all REST services class or methods

@chickenchickenlove is already working on this.

Since Jul 18, 2024.

All Central Dogma APIs use JSON (Patch) to exchange data. A Central Dogma server can't handle other types such as XML or YAML.

Currently, the request `content-type` is not specified in some API methods.
https://github.com/line/centraldogma/blob/24603eb149d3945fde2cc1ced71a9efdcbc231fe/server/src/main/java/com/linecorp/centraldogma/server/internal/api/ContentServiceV1.java#L187-L191
That results in generating a converter not found error message if `content-type` is missing.
For example, a commit is sent without `content-type`, `No suitable request converter` is returned from which users don't know what is wrong.
```sh
$ curl -XPOST "http://127.0.0.1:36462/api/v1/projects/foo/repos/bar/contents" \
-H "Authorization: Bearer appToken-***" \
-d '{
"commitMessage" : {
"summary": "hello",
"detail": "a",
"markup": "MARKDOWN"
},
"changes" : [
{
"path" : "/foo0.json",
"type" : "UPSERT_JSON",
"content" : {"a": "bar2"}
}
]
}'
{"exception":"java.lang.IllegalArgumentException","message":"No suitable request converter found for a @RequestObject 'CommitMessageDto'"}%
```

If `@ConsumeJson` is added to the method, `405 Method Not Allowed` is returned which would make it easier to identify the cause.