Convert datetime objects to snowflake ids for max_id, min_id and since_id

[Kudusch]

As Mastodon uses Snowflake IDs for statuses, it is possible to convert a date and time to a Snowflake ID (with a relatively low resolution). Giving users the ability to provide a POSIXct for max_id, min_id, and/or since_id could make it easier to search for posts between two dates/times.

The Python API client does this as well (and I found it very useful!): https://mastodonpy.readthedocs.io/en/stable/01_general.html#snowflake-ids

One way to implement this could be changing handle_params in utils. Converting a POSIXct datetime to a snowflake id can by done by bitshifting the timestamp like this: as.numeric(datetime)*(2^16))*1000

Might make sense to do a is(max_id, "POSIXct") check before converting, like so:

handle_params <- function(params, max_id, since_id, min_id) {
    if (!missing(max_id)) {
        if(is(max_id, "POSIXct")) {
            params$max_id <- as.numeric(max_id)*(2^16))*1000
        } else {
           params$max_id <- max_id
        }
    }
    if (!missing(since_id)) {
        if(is(max_id, "POSIXct")) {
            params$since_id <- as.numeric(since_id)*(2^16))*1000
        } else {
           params$since_id <- since_id
        }
    }
    if (!missing(min_id)) {
        if(is(min_id, "POSIXct")) {
            params$min_id <- as.numeric(min_id)*(2^16))*1000
        } else {
           params$min_id <- min_id
        }

    }
    params
}

[chainsawriot]

@Kudusch Are you interested in providing a PR? Thank you very much!

As this code repeats 3 times, it might make sense to spin it off as a helper function

 if(is(max_id, "POSIXct")) {
            params$since_id <- as.numeric(since_id)*(2^16))*1000
        } else {
           params$since_id <- since_id
        }

handle_id <- function(x) {
    ## convert x to snowflake id if it is POSIXct
    if (is (x, "POSIXct")) {
        return(as.numeric(x)*(2^16))*1000)
    }
    x
}

if (!missing(max_id)) {
    params$max_id <- handle_id(max_id)
}