feat: Add the ability to define filename formats per creator

[ddirty830]

I found I kept swapping filename formats depending on who the creator was. So I made these changes.

{
"PaidPostFileNameFormat": "{postedAt}.{filename}",
"PostFileNameFormat": "{postedAt}.{filename}",
"PaidMessageFileNameFormat": "{createdAt}.{filename}",
"MessageFileNameFormat": "{createdAt}.{filename}",
"CreatorConfigs": {
  "creatorUserName1": {
    "PaidPostFileNameFormat": "{postedAt}.{rawText}",
    "PostFileNameFormat": "{postedAt}.{rawText}",
    "PaidMessageFileNameFormat": "{postedAt}.{rawText}",
    "MessageFileNameFormat": "{postedAt}.{rawText}"
  },
  "creatorUserName2": {
    "PaidPostFileNameFormat": "{postedAt}.{rawText}",
    "PostFileNameFormat": "{postedAt}.{rawText}",
    "PaidMessageFileNameFormat": "{postedAt}.{rawText}",
    "MessageFileNameFormat": "{postedAt}.{rawText}"
  }
}

If a creator isn't in the CreatorConfigs, or that creator doesn't have a format defined, it'll fall back to the root format.

[ddirty830]

Did a quick rebase to capture the latest changes from master.

[ddirty830]

Some other changes I made:

• I reworked a lot of the static members for Auth and Config, so they're instanced and passed to class constructors instead of grabbing globals.
• I removed extraneous method parameters since the classes had access to Auth/Config directly now
• Retooled the Config screen so if new options are added in the future, the new Property in the Config class just needs to be decorated with the [ToggleableConfig] to show up and be editable

[melithine]

I like this; I think it makes https://github.com/sim0n00ps/OF-DL/issues/341 moot, as I can just use this functionality to achieve the same goal.