feat(cli): Add vault ssh certificate credential library

internal/tests/cli/boundary/_vault.bash

@@ -0,0 +1,47 @@
+
+function vault_write_boundary_policy() {
+  (
+  cat <<EOF
+path "auth/token/lookup-self" {
+  capabilities = ["read"]
+}
+
+path "auth/token/renew-self" {
+  capabilities = ["update"]
+}
+
+path "auth/token/revoke-self" {
+  capabilities = ["update"]
+}
+
+path "sys/leases/renew" {
+  capabilities = ["update"]
+}
+
+path "sys/leases/revoke" {
+  capabilities = ["update"]
+}
+
+path "sys/capabilities-self" {
+  capabilities = ["update"]
+}
+EOF
+  ) | vault policy write boundary-controller -
+}
+
+function create_vault_token() {
+  vault token create \
+    -format=json \
+    -no-default-policy=true \
+    -policy="boundary-controller" \
+    -orphan=true \
+    -period=2m \
+    -renewable=true | \
+    jq -r '.auth.client_token'
+}
+
+function skip_if_no_vault() {
+  if [[ -z $VAULT_ADDR ]] || [[ -z $VAULT_TOKEN ]]; then
+    skip "vault environment variables \$VAULT_ADDR and \$VAULT_TOKEN not set"
+  fi
+}