Imgur: Allow use with an account and album

[half-duplex]

I'd like to have the ability to collect and manage uploaded images. The easiest way to do this is to upload to an Imgur account instead of anonymously, and to an album.

As I said in the other PR, I don't really speak golang, so I appreciate comments.

Note: Imgur's documentation states that access tokens are valid for 1 month, but the ones the API returns seem to not expire for 10 years. If they ever change this, bots in this configuration running for over 1 month will need a restart to refresh the token.

[jwflory]

Thanks for the extensive documentation on this Pull Request @half-duplex. It's especially appreciated.

I just changed a setting for the CircleCI pipeline where it should properly build Pull Requests submitted from a forked repository. If you push a new commit to this Pull Request, the CI builds should execute completely.

[jwflory]

All tests passed except the Go 1.17 tests. This is because this test suite also uses a secret credential to upload the test coverage results to CodeClimate. The secret credential is only available on branches on this repository.

So, all test suites are passing here. There is some feedback from CodeClimate about too many return statements in the getImgurAccessToken function, but I'm not sure this is something we have to mitigate now.

[Tjzabel]

Overall looks really good! Just had a few comments and spelling error.

Also not sure if there's a better way to format the returns in imgur.go. For me I'm fine with the number of returns.

[jwflory]

LGTM. @Tjzabel or any @RITlug/teleirc-developers-commit-access member, want to take a final pass here?

[jwflory]

I rebased this PR on the latest changes in main via the GitHub web interface.

[Tjzabel]

Looks good! Thanks for making these changes 👍