📕✨：add initial accessions: mount & umount commands (umount later)

[DerekNonGeneric]

Pull Request Purpose

Make a selection on the purpose(s) of your changes.

This PR contains the following:

• 🐞🔧 bugfixing (🐜/🦟/🐛/🦗/🐝 et al.)
• 🆕🎏 implementation of new feature(s)
• ♻️ refactoring(s)
• 📄 documentation modification(s)
• 🔮 other

Testing

Have you included any tests in your submission?

• yes (bugfixes and features will not be merged without
  tests)
• no

Breaking Changes

Have you modified any aspect public API surface (i.e., caused breakage)?

• yes (breaking changes will not be merged unless
  necessary)
• no

Description

A concise recap summarily detailing what all are the changes being made.

Rich diff PR hyperlink:

• https://github.com/OpenINF/docker-fisher/pull/22/files?short_path=69d22bb#diff-69d22bb6e6ff8dd7f0a62a0de98d625c576ffaac93e60f208173a159e4c45d84#mount

[sweep-ai]

Apply Sweep Rules to your PR?

• Apply: All new business logic should have corresponding unit tests.
• Apply: Refactor large functions to be more modular.
• Apply: Add docstrings to all functions and file headers.

[OpenINFbot]

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