Formalise blueprint framework

[zacharlie]

I have outlined the concept of solution blueprints as I understand them in the roadmap https://github.com/kartoza/osgs/pull/43

I believe we need to invest a fair bit of effort into streamlining the process of creating custom/ external blueprints and what aspects/ components they are expected to affect.

Some key considerations off the top of my head include:

• Pushing user configs and/ or osgs-admin config documents: This could include default users and roles, org ssl certs, active services, plugins (e.g. geoserver), app name and branding etc
• Blueprint structure and process: What is the expected directory tree? What components can be added or configured?
• Lifecycle hooks: e.g. Bootstrap the creation of schemas and tables, populating tables with sample data, run ODM process, cleanup operations and retention policy management etc
• App specific config: e.g. pushing device id's, vpn config or a fqdn into the stack or particular nodes
• App specific overrides: override instead of merge with existing data, e.g. hugo themes etc

Some aspects we might expect to be included in the blueprints I can think of without digging into what's available:

• Node red nodes, plugins, dashboards etc
• ODM imagery/ processes/ config
• QGIS projects
• Mergin/ input projects
• Custom maps and pages using the static site

For all of these types of components we need a way to get them into the stack at/ before deploy and merge/ sync them with the default data without introducing implicit conflicts

[zacharlie]

I have detailed my recommendations for approaching this in #86 and started prelim development of a PoC at https://github.com/zacharlie/osgs-sl

The gist of it is that a separate application acts as a UI, repository, and engine for blueprint operations, as well as provides better UX for users, e.g. wysiwyg markdown editor and form for new hugo map article creation

This is abstracted from the stack itself and acts as a CMS with "click to run" deployments, e.g. A "Manhole Asset Management" solution could create a db with the specified schema, generate a mergin project, publish a map service, and create the necessary dashboards from template files.