[WIP] read xlsx with Chartsheet. closes #123

[JanMarvin]

No description provided.

[JanMarvin]

Codecov Report

Merging #124 (19dfd15) into main (1eb26f2) will increase coverage by 0.86%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #124      +/-   ##
==========================================
+ Coverage   59.30%   60.17%   +0.86%     
==========================================
  Files          39       39              
  Lines        7306     7307       +1     
==========================================
+ Hits         4333     4397      +64     
+ Misses       2973     2910      -63     

Impacted Files	Coverage Δ
R/loadWorkbook.R	90.10% <100.00%> (+4.97%)	⬆️
R/class-workbook.R	53.02% <0.00%> (+2.09%)	⬆️

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[JanMarvin]

I wanted to use something like this, but somehow the ids did not match:

# sheets name rid
sheets <- rbindlist(xml_attr(workbook_xml, "workbook", "sheets", "sheet"))
sheets <- sheets[sheets$`r:id` != "",]

# sheets type
wb_rels_xml <- rbindlist(xml_attr(workbookRelsXML, "Relationships", "Relationship"))

# combine both
sheets <- merge(
  sheets, wb_rels_xml,
  by.x = "r:id", by.y = "Id",
  all.x = TRUE, all.y = FALSE
)

# get typ and full path
sheets$typ <- basename(sheets$Type)
sheets$target <- stri_join(xmlDir, "/xl/", sheets$Target)