add on demand system test (not run by default in ci)

tests/RobotFramework/requirements/requirements.txt

@@ -2,7 +2,7 @@ dateparser~=1.2.0
 paho-mqtt~=1.6.1
 python-dotenv~=1.0.0
 robotframework~=7.0.0
-robotframework-c8y @ git+https://github.com/thin-edge/robotframework-c8y.git@0.37.2
+robotframework-c8y @ git+https://github.com/thin-edge/robotframework-c8y.git@0.38.1
 robotframework-aws @ git+https://github.com/thin-edge/robotframework-aws.git@0.0.9
 robotframework-debuglibrary~=2.5.0
 robotframework-jsonlibrary~=0.5

tests/RobotFramework/tests/cumulocity/registration/cumulocity_ca.robot

@@ -0,0 +1,31 @@
+*** Settings ***
+Resource        ../../../../resources/common.resource
+Library         Cumulocity
+Library         ThinEdgeIO
+Library         String
+
+Test Setup      Custom Setup
+
+Test Tags       theme:c8y    test:on_demand
+
+
+*** Test Cases ***
+Register Device Using Cumulocity CA
+    ${credentials}=    Bulk Register Device With Cumulocity CA    ${DEVICE_SN}
+    ${DOMAIN}=    Get Cumulocity Domain
+    Execute Command    tedge config set c8y.url "${DOMAIN}"
+    Execute Command    tedge cert download c8y --device-id "${DEVICE_SN}" --token "${credentials.password}"
+    Execute Command    tedge connect c8y
+
+
+*** Keywords ***
+Get Cumulocity Domain
+    ${DOMAIN}=    Replace String Using Regexp    ${C8Y_CONFIG.host}    ^.*://    ${EMPTY}
+    ${DOMAIN}=    Strip String    ${DOMAIN}    characters=/
+    RETURN    ${DOMAIN}
+
+Custom Setup
+    ${DEVICE_SN}=    Setup    skip_bootstrap=${True}
+    Execute Command    test -f ./bootstrap.sh && ./bootstrap.sh --no-bootstrap --no-connect || true
+
+    Set Test Variable    $DEVICE_SN