TLS configure for OIDC connector (#1632)

connector/github/github.go

connector/oauth/oauth.go

connector/oidc/oidc.go

connector/openshift/openshift.go

connector/openshift/openshift_test.go

go.mod

pkg/httpclient/httpclient.go

pkg/httpclient/httpclient_test.go

pkg/httpclient/readme.md

pkg/httpclient/testdata/rootCA.key

pkg/httpclient/testdata/rootCA.pem

pkg/httpclient/testdata/rootCA.srl

pkg/httpclient/testdata/server.crt

pkg/httpclient/testdata/server.csr

pkg/httpclient/testdata/server.csr.cnf

pkg/httpclient/testdata/server.key

pkg/httpclient/testdata/v3.ext