Enable [forbidigo](https://github.com/ashanbrown/forbidigo) linter which
forbids print statements. Will check how to integrate this with the
smallest impact possible, so a few `nolint` comments will likely be
required. Plan is to just go through the issues and either:
- Remove the print if it is nonsensical
- Add a `//nolint` directive if it makes sense
I don't plan on investigating the individual issues any further.
<details>
<summary>Initial Lint Results</summary>
```
modules/log/event.go:348:6: use of `fmt.Println` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Println(err)
^
modules/log/event.go:382:6: use of `fmt.Println` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Println(err)
^
modules/queue/unique_queue_disk_channel_test.go:20:2: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("TempDir %s\n", tmpDir)
^
contrib/backport/backport.go:168:2: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("* Backporting %s to %s as %s\n", pr, localReleaseBranch, backportBranch)
^
contrib/backport/backport.go:216:4: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("* Navigate to %s to open PR\n", url)
^
contrib/backport/backport.go:223:2: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("* `xdg-open %s`\n", url)
^
contrib/backport/backport.go:233:2: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
cmd/serv.go:175:4: use of `println` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
println("Hi there! You've successfully authenticated with the deploy key named " + key.Name + ", but Gitea does not provide shell access.")
^
cmd/serv.go:177:4: use of `println` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
println("Hi there! You've successfully authenticated with the principal " + key.Content + ", but Gitea does not provide shell access.")
^
cmd/serv.go:179:4: use of `println` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
println("Hi there, " + user.Name + "! You've successfully authenticated with the key named " + key.Name + ", but Gitea does not provide shell access.")
^
cmd/serv.go:181:3: use of `println` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
println("If this is unexpected, please log in with password and setup Gitea under another user.")
^
cmd/serv.go:196:5: use of `fmt.Print` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Print(`{"type":"gitea","version":1}`)
^
tests/e2e/e2e_test.go:54:3: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("Error initializing test database: %v\n", err)
^
tests/e2e/e2e_test.go:63:3: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("util.RemoveAll: %v\n", err)
^
tests/e2e/e2e_test.go:67:3: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("Unable to remove repo indexer: %v\n", err)
^
tests/e2e/e2e_test.go:109:6: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("%v", stdout.String())
^
tests/e2e/e2e_test.go:110:6: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("%v", stderr.String())
^
tests/e2e/e2e_test.go:113:6: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("%v", stdout.String())
^
tests/integration/integration_test.go:124:3: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("Error initializing test database: %v\n", err)
^
tests/integration/integration_test.go:135:3: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("util.RemoveAll: %v\n", err)
^
tests/integration/integration_test.go:139:3: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)
fmt.Printf("Unable to remove repo indexer: %v\n", err)
^
tests/integration/repo_test.go:357:4: use of `fmt.Printf` forbidden by pattern `^(fmt\.Print(|f|ln)|print|println)$` (forbidigo)