refactor: fetch by default

[dshemetov]

closes #144
closes #119

• fetch_args_list() has these arguments, open to better/clearer naming suggests

#' @param fields a list of epidata fields to return, or NULL to return all
#'  fields (default) e.g. c("time_value", "value") to return only the
#' time_value and value fields or c("-direction") to return everything except
#' the direction field
#' @param disable_date_parsing disable automatic date parsing
#' @param disable_data_frame_parsing disable automatic conversion to data frame; this
#'   is only supported by endpoints that only support the 'classic' format (non-tabular)
#' @param return_empty boolean that allows returning an empty tibble if there is no data
#' @param timeout_seconds the maximum amount of time to wait for a response
#' @param base_url base URL to use
#' @param make_call boolean that allows skipping the call to the API and instead
#'  returns the `epidata_call` object (useful for debugging)
#' @param debug boolean that allows returning the raw response from the API
#' @param format_type the format to request from the API, one of classic, json, csv; this
#'  is only used by `fetch_debug`

• all endpoints now fetch by default
• with_base_url has been absorbed into fetch args and made internal which should close with_base_url sounds like it follows the withr/etc. pattern but doesn't #82
• added automated ci actions (automatically documents, styles, and lint should now actually complain properly)

TODO:

• look over the vignette text to make sure it still reads right

[dsweber2]

Generally pretty happy with this, made a number of small docs changes. To keep the format of the flags the same (i.e. they're all off by default), maybe make_call should be dry_run or something like that?

I separated fetch_args_list into a separate reference page, because all the parameters of create_epidata_call, fetch and fetch_args_list were mixed together.