Include tree and text data.frame in SRCGrob

[dan-knight]

Description

Closes #95. Sets up export of the final tree and text data used by the plot under $input.data$tree and $input.data$text`. This differs from the input data by including any replacements to default values and data transformations as a result of the internal prep functions. Exposing this data will allow users to tweak an existing plot more easily.

At this point, there is no file export. I felt that including this functionality within the resulting plot object would allow users to use the data more flexibly. If CSV output is vital, it will be trivial to add - just another parameter and a standard write.csv() call at the end of the function.

Closes #...

Checklist

• [x] This PR does NOT contain Protected Health Information (PHI). A repo may need to be deleted if such data is uploaded.
  Disclosing PHI is a major problem[^1] - Even a small leak can be costly[^2].

• [x] This PR does NOT contain germline genetic data[^3], RNA-Seq, DNA methylation, microbiome or other molecular data[^4].

[^1]: UCLA Health reaches $7.5m settlement over 2015 breach of 4.5m patient records [^2]: The average healthcare data breach costs $2.2 million, despite the majority of breaches releasing fewer than 500 records. [^3]: Genetic information is considered PHI. Forensic assays can identify patients with as few as 21 SNPs [^4]: RNA-Seq, DNA methylation, microbiome, or other molecular data can be used to predict genotypes (PHI) and reveal a patient's identity.

• [x] This PR does NOT contain other non-plain text files, such as: compressed files, images (e.g. .png, .jpeg), .pdf, .RData, .xlsx, .doc, .ppt, or other output files.

  To automatically exclude such files using a .gitignore file, see here for example.

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• [x] The name of the branch is meaningful and well formatted following the standards, using [AD_username (or 5 letters of AD if AD is too long)]-[brief_description_of_branch].

• [x] I have added the major changes included in this pull request to the CHANGELOG.md under the next release version or unreleased, and updated the date.

[whelena]

I approved this but don't have merge permissions, did you want to merge this to main?