Add wrapper function for running internal references

### If you are filing this issue based on a specific GitHub Discussion, please link to the relevant Discussion.

Part of #1080

### Describe the goals of the changes to the analysis module.

In https://github.com/AlexsLemonade/OpenScPCA-analysis/pull/1126, a function was added to the `infercnv-consensus-cell-type` module to prepare internal normal references, i.e. a normal reference that uses cells only from the given library. The function was implemented to be specific to ewings data from SCPCP000015.

In the future if we want to run other projects with internal references, we will need to update this code to include project-specific functions and an overall wrapper function to call from the inferCNV script.

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Here are the relevant sections of code with `TODO`s:

https://github.com/AlexsLemonade/OpenScPCA-analysis/blob/e540d8234f34a8e85a9ad8d4ecd8275f15443169/analyses/infercnv-consensus-cell-type/scripts/01_run-infercnv.R#L240-L250

https://github.com/AlexsLemonade/OpenScPCA-analysis/blob/e540d8234f34a8e85a9ad8d4ecd8275f15443169/analyses/infercnv-consensus-cell-type/scripts/utils.R#L23-L24

https://github.com/AlexsLemonade/OpenScPCA-analysis/blob/e540d8234f34a8e85a9ad8d4ecd8275f15443169/analyses/infercnv-consensus-cell-type/scripts/utils.R#L38-L47

### What will your pull request contain?

Re-organized functions

### Will you require additional software beyond what is already in the analysis module?

No, only renv

### Will you require different computational resources beyond what the analysis module already uses?

No

### If known, when do you expect to file the pull request?

This PR will be filed as needed.

Start by reading the TODO sections in analyses/infercnv-consensus-cell-type/scripts/01_run-infercnv.R and scripts/utils.R, then inspect the existing internal-reference function added for the ewings data. Reorganize the project-specific functions and add the wrapper callable from the inferCNV script, with internal references supported without additional software beyond renv.

Written by the indexing model from the issue text.