[Feature/agent_framework] Adding installed plugins validation

[joshpalis]

Description

This PR adds a new field required_plugins to the workflow_step json which is used to determine if the workflow step's corresponding plugin is currently installed within the local node. Additionally, this PR adds validation when creating (with validation) and provisioning to check if the given graph has all the required plugins prior to executing.

The following example uses a create connector node with an intentionally modified required plugin named test-plugin to demonstrate how the validation works :

Creating the workflow :

curl -i -XPOST "localhost:9200/_plugins/_flow_framework/workflow" -H "Content-Type:application/json" --data '{"name":"create-connector-register-deploy-model","description":"test case","use_case":"TEST_CASE","version":{"template":"1.0.0","compatibility":["2.12.0","3.0.0"]},"workflows":{"provision":{"nodes":[{"id":"workflow_step_1","type":"create_connector","user_inputs":{"name":"OpenAI Chat Connector","description":"The connector to public OpenAI model service for GPT 3.5","version":"1","protocol":"http","parameters":{"endpoint":"api.openai.com","model":"gpt-3.5-turbo"},"credential":{"openAI_key":"12345"},"actions":[{"action_type":"predict","method":"POST","url":"https://${parameters.endpoint}/v1/chat/completions"}]}},{"id":"workflow_step_2","type":"register_remote_model","previous_node_inputs":{"workflow_step_1":"connector_id"},"user_inputs":{"name":"openAI-gpt-3.5-turbo","function_name":"remote","description":"test model"}},{"id":"workflow_step_3","type":"deploy_model","previous_node_inputs":{"workflow_step_2":"model_id"}}],"edges":[{"source":"workflow_step_1","dest":"workflow_step_2"},{"source":"workflow_step_2","dest":"workflow_step_3"}]}}}'

HTTP/1.1 201 Created
content-type: application/json; charset=UTF-8
content-length: 38

{"workflow_id":"n-jqaYwBsLRi2-luOv83"}

Provisioning the workflow results in an error that states that the create_connector step requires the test-plugin to be installed

curl -i -XPOST "localhost:9200/_plugins/_flow_framework/workflow/n-jqaYwBsLRi2-luOv83/_provision"
HTTP/1.1 400 Bad Request
content-type: application/json; charset=UTF-8
content-length: 108

{"error":"The workflowStep create_connector requires the following plugins to be installed : [test-plugin]"}

Issues Resolved

#126
Part of #88

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[dbwiddis]

Great job! First pass, some suggestions.

[dbwiddis]

Approved, suggestions above remain suggestions for consideration but OK as is.