get_table returns a table's metadata as a nested list.
In addition to a regular error, the condition bigrquery_notFound
(which can be handled via base::tryCatch())
is raised if the table could not be found.
exists_table merely checks if a table exists, and returns
either TRUE or FALSE.
# NOT RUN {str(get_table("publicdata", "samples", "natality"))
str(get_table("publicdata", "samples", "gsod"))
str(get_table("githubarchive", "github", "timeline"))
# }# NOT RUN {# }