Add methods for real cloud in acceptance

[outcatcher]

Load cofiguration from clouds.yaml and use it later in acceptance tests

Example usage:

func (p *PluginTest) TestPrepareCloud() {
    t := p.T()

    cloud := p.prepareCloud()
    require.NotEmpty(t, cloud)
    t.Log(cloud)
}

[otc-zuul[bot]]

Build succeeded.

:heavy_check_mark: otc-golangci-lint SUCCESS in 2m 29s :heavy_check_mark: golang-make-vet SUCCESS in 2m 33s :heavy_check_mark: golang-make-test SUCCESS in 2m 39s :heavy_check_mark: goreleaser-build SUCCESS in 4m 24s