API support to submit MIDI files

I'm not sure how "curated" we want BitMIDI to be, but if we provide API support for authenticated users to POST MIDI files, this will allow users to perform their own submissions in the long run. (Things like web forms, and bots).

This is quite the substantial amount of work, and I think can be logically broken down into the following features:

### Authenticate API access
Provide the ability to authenticate specific requests that need to be locked down.

e.g.

```
$ curl -X POST -i -H "Content-Type: application/json" -u basic_username:basic_password https://bitmidi.com/api/my_secure_endpoint
```
This will probably involve a new table in the current database.

Intentionally doing only basic auth only for now, so that we can add in token based auth later if needed.

### API support for submitting a MIDI
Provide the following APIs:

Submitting a MIDI
```
POST /api/upload?whatever_query_strings_needed_for_unique_identification_of_new_file=blah
content-type: audio/midi
Authorization: Basic test_user:test_pwd

{
"status": "verifying"
"job_id": 6969
"midi_id": ""
}
```

Querying a submitted MIDI
```
GET /api/upload_status?job_id=6969

{
"status": "success"
"job_id": 6969
"midi_id" 1234
}
```