Programmatically get IRC-compatible OAuth token for bot

[oelna]

@BarryCarlyon

Usually an access token is only valid for around four hours, so I don’t bother trying the access token, when my bot (re)starts it just uses the refresh proceedure

That seems a good practice. As a beginner, I found it challenging to get access_token at all, so once I had one, I valued it a lot. But it now seems the refresh_token is the actually valuable one. Great tip!