Implement Backstage Custom Action for odo init

[rm3l]

As a Backstage contributor contributing a template to my organization, I want to have a set of custom actions allowing me to execute odo from Backstage So that my template could provide additional functionality.
For example, my template could prompt users to select a Devfile, and then using this information, the template could include action steps to generate a starter project off of the Devfile selected, using odo init.

Acceptance Criteria

• It should accept as input: devfile name, version and starter project
• It should be easily installable into any Backstage instance, e.g., using an NPM package
• It should expose a devfile:odo:component:init custom action executing odo init
• Optionally, it could expose a generic devfile:odo:command custom action executing any odo command
• It should take care of security, as we will be executing commands from user input.

Remaining:

• Question of how to distribute the odo binary with this custom action plugin. Currently, we assume the integrator has to install odo in the environment the Backstage instance is running in

Related Epic: #7114

[rm3l]

Marking this as complete. I created a custom action plugin and published it. For now, this is available as a POC under my personal GH and NPM accounts: https://github.com/rm3l/backstage-odo-devfile-plugin/blob/main/packages/scaffolder-odo-actions-backend/README.md

We'll create additional issues based on the next steps about this.

Remaining things to do:

• How to distribute the odo binary (see [Research][Spike] Backstage Golden Path Template (GPT) for odo init #7086 (comment))
• Move this away from my personal account and NPM package
• Proper tests
• Release process: automatically publish the NPM module

/close