Re-assess exported functions

@LDSamson @aclark02-arcus @jthompson-arcus

Should function be exported (Y/N)?

Function	Leon (Y/N)	Aaron (Y/N)	Jeff (Y/N)
`add_missing_columns()`	N		N
`adjust_colnames()`
`app_ui()`			N
`bind_rows_custom()`	N		N
`check_appdata()`	N		N
`clean_dates()`	N		N
`collapse_column_vals()`
`collapse_fct_levels()`
`collect_query_data()`
`cols_to_char()`
`create_report()`
`create_table()`			? This function only makes sense for outputs from `get_appdata()`. Having said that, do we have to export to allow users to create their own S3 methods?
`create_unique_id()`
`custom_plot_theme()`
`datatable_custom()`	N		N
`date_cols_to_char()`	N		N
`db_create()`
`db_get_query()`
`db_get_review()`
`db_save()`
`db_save_review()`
`db_slice_rows()`
`db_temp_connect()`
`db_update()`
`expand_columns()`	N		N
`fig_barplot()`
`fig_boxplots()`
`fig_timeline()`
`fig_timeseries()`
`fix_multiple_choice_vars()`
`get_appdata()`
`get_available_data()`
`get_base_value()`
`get_db_connection()`
`get_ggplot_layer_names()`	N		N
`get_max_time()`
`get_meta_vars()`	N		N
`get_metadata()`
`get_raw_csv_data()`	Y		Y
`get_review_data()`
`get_static_overview_data()`
`get_test_results()`	Y Currently I need this for updating the package test report. Alternatively, I could add this function to our internal package with API functions.		Y
`get_timeline_data()`	N		N
`get_unique_vars()`	N		N
`initialize_credentials()`	N		N
`is_date()`	N		N
`merge_meta_with_data()`	Y I need this for our automated workflows. Probably also nice to have for development.		Y
`order_string()`	N		N
`plotly_figure()`
`remove_boxplot_outliers()`	N		N
`run_app()`	Y	Y	Y
`select_report_data()`
`simplify_string()`
`summarize_review_data()`
`time_stamp()`	N		N
`title_case()`
`update_review_data()`
`vector_select()`	N		N

openpharma / clinsight

Re-assess exported functions #144