[BTG-32] Uploaded autodoc sample

Description

Automatically upload ManagedLedger documentation to the dedicated branch. CI, assuming that this branch exists, merges the recent master to this branch and then commits the new version of the documentation.

A similar approach can be taken in other repositories.

Example of branch we upload to: https://gitlab.com/morley-framework/morley/commits/autodoc/martoon/btg32-upload-doc-sample

Related issue(s)

https://issues.serokell.io/issue/BTG-33

✅ Checklist for your Merge Request

Related changes (conditional)

• Tests (see short guidelines)

  • If I added new functionality, I added tests covering it.
  • If I added non-trivial functionality to the contract, I added new entrypoints to test scenario and tested it on alphanet (see scripts).
  • If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.

• Documentation

  • I checked whether I should update the docs and did so if necessary:
    • README
    • Haddock
    • docs/

Stylistic guide (mandatory)

• My commits comply with the following policy.
• My code complies with the style guide.

Problem-specific

• CI config does not refer to this branch.