[FR] add Yandex as oauth2 support

[fazlerabbi37]

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Description

goth already supports Yandex. It would be great to see Yandex as oauth2 provider as many organizations (including mine) already usages Yandex.

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I wish I was familiar with Golang, as looking at #4476 it doesn't seem to complicated, though that could be my lack of experience. Would be a really great see this implemented.

Screenshots

[fazlerabbi37]

Thank you @anatolym and @lafriks ❤️