Unite all configuration

[bencooper222]

From what I can see, the big places to configure Vaken are

• application.ts
• constants.ts
• strings.json

and I'm sure there is more that I'm missing in little lines in random files.

I don't think there's a reason to separate all configuration from code - that leads to complexity in another way but if we're going to have several files whose purpose is only config, I think we should try to at least get them in one directory (and as .ts files).