Add filepaths to plotNames_by_site.csv

[lindsayplatt]

1. Stage height data needs to be csv files w/ dateTime (yyyy-mm-dd) and gageHeight columns.
2. Add file paths to plotNames_by_site.csv (within text editor, like notepad ++). Use column name gageHeight_files
3. Add code to grab gageHeight_files and use instead of NWIS.

[sbmarsh-USGS]

df <- read_excel("M:/Lakes/9KB25/Silver_Cumberland/Stage/silver_cumberland_stage.xlsx")

Do decimalDate workaround for Lake Winnebago.

[lindsayplatt]

Code changes (don't need csv, can use Excel w/ readxl package):

• [x] Create function that takes a site number and returns the stage filepath from the plotNames_by_site.csv
• [x] In renderLakeReport, call the new function only if it's creating a stage hydrograph. The new object should be named filePath.
• [x] Change read.csv to read_excel (and add library(readxl)) to stagehydrograph.Rmd.
• [x] makeStageHydrograph_file function does not need the datetime_colname and gageheight_colname titles
• [x] Add to makeStageHydrograph_file to properly change dates to a date format, and handle the Lake Winnebago dates with:

gage_height <- gage_height %>% 
  mutate(decimal.date = as.numeric(decimal.date),
         dateTime = date_decimal(decimal.date))