Add a whois endpoint

[puppy0cam]

This pull request is intended for a server-side implementation of necessary data for a whois command within the client.

Current draft of endpoint documentation:

Player Verification

This is where the client can retrieve the Discord identity of a player based on their Minecraft Name without initiating an auth code check.
This can be useful for debugging the current state of the user.

GET /player/{Player Name}

Possible Errors:

• Missing Player Name Attribute

This endpoint finds the discord identity of a player.

Required Headers:

1. Content-Type: application/json
2. Authorization: <webserver token>

Attribute	Type	Description
Player Name	string	The Minecraft player name

The Player Name is the Minecraft player Name stripped of all the dashes. The server will provide
the following response if everything went alright, otherwise an error may occur.

Response Body

No Data - Response

The player does not exist

Attribute	Type	Description
player_type	string	Possible types are described below

• "not_found": This player could not be found
• "outdated_spec": special state indicating that the client must be updated
  in order to account for a change that is not backwards compatible.

Unlinked Player - Response

Attribute	Type	Description
player_id	string	The Minecraft UUID for the player
player_type	string	Will be "pending_auth" - An auth code has been generated for the player, however the code has not been submitted in Discord.

Valid Player - Response

The player exists, here is the linked account

Attribute	Type	Description
snowflake	string	The Discord snowflake (id) of the player
player_id	string	The Minecraft UUID for the player
player_type	string	Possible types are described below

• "player": This is a regular player who is allowed on the server.
• "alt": This is an alt account of a staff member
• "banned": This person is banned from using the bot and auth server.

Errors

Missing Player Name Attribute

{
  "errcode": "NO_PLAYER_ID",
  "message": "There wasn't a player ID provided"
}

[puppy0cam]

A potential option for preventing rate limits from being hit is to have the client limit permissions to the command be limited to staff. This would help ensure that a staff member can investigate a player easily without having to access discord.
This does not meet what my intention for use of the command should be as I think it would be ideal if regular players were permitted to use it to find the owner of a plot if they want to contact them for a merge or transfer. The fact that the discord command pings the target is not ideal for those purposes as they might decide otherwise upon finding the identity. It's also inconvenient, and knowledge of the discord command for this does not appear to be very prevalent.

[puppy0cam]

This should be achievable by having the user copy text that will be interpreted as a @ mention for them by their Discord client. This will negate the need to lookup their user data from Discord itself
Tellraw data may look like so:

[
    {
        "text": "This user exists, click ",
        "color": "yellow"
    },
    {
        "text": "here",
        "bold": true,
        "color": "yellow",
        "clickEvent": {
            "action": "copy_to_clipboard",
            "value": "<@201600394353311744>"
        }
    },
    {
        "text": " to copy their username to mention them in Discord",
        "color": "yellow"
    }
]