Create flow to update subgraph docs on Dev-Portal

[banasa44]

Description

This PR introduces everything needed to generate Subgraph documentation and send it to the Developer-Portal. It mimics the workflows on SDK and OSX/contracts.

It doesn't generate all the subraph documentation as the reference-guide documentation is generated in the Dev-Portal itself as we are using a plugin from Docusaurus that generates it. What we are providing though is the result of the introspection query needed to generate the subgraph docs.

The PR includes 2 query example samples as this will be the actual workflow, the test for these queries will be done in following-up tasks.

Task ID: OS-1051

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have selected the correct base branch.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.
• I ran all tests with success and extended them if necessary.
• I have updated the CHANGELOG.md file in the root folder.
• I have updated the DEPLOYMENT_CHECKLIST file in the root folder.
• I have updated the UPDATE_CHECKLIST file in the root folder.

[heueristik]

Let's make sure that the workflow does not run on closing a PR.
If this was adapted from the SDK workflows, let's make sure to fix it there as well.