* Add support for Sensu Go notification channel

Similar to current support for the older "Core" version of
Sensu, this commit add support for the newer version.

Closes #19908

Signed-off-by: Todd Campbell <todd@sensu.io>

* fix linter errors

Signed-off-by: Todd Campbell <todd@sensu.io>

* Apply suggestions from code review

PR review suggestions

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Fix no new variables error

* Replace convey testing with testify

Signed-off-by: Todd Campbell <todd@sensu.io>

* Wording suggestions

Signed-off-by: Todd Campbell <todd@sensu.io>

* Add docker compose environment for testing/maintenance

Signed-off-by: Todd Campbell <todd@sensu.io>

* Renamed and fixed docker-compose.yaml to work in devenv

Signed-off-by: Todd Campbell <todd@sensu.io>

* Change sensugo web UI port to 3080 so as not to conflict with grafana

Signed-off-by: Todd Campbell <todd@sensu.io>

* Apply suggestions from code review

Set the API key as a secure value.

Co-authored-by: Sofia Papagiannaki <papagian@users.noreply.github.com>

* Add Sensu Go information to notifications doc

Signed-off-by: Todd Campbell <todd@sensu.io>

* Update pkg/services/alerting/notifiers/sensugo.go

Co-authored-by: Sofia Papagiannaki <papagian@users.noreply.github.com>

* change assert to require for Error/NoError tests

Signed-off-by: Todd Campbell <todd@sensu.io>

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>
Co-authored-by: Sofia Papagiannaki <papagian@users.noreply.github.com>