clean up and export crc32c function (#22274)
* clean up and export crc32c function
* added PR to NEWS
* restore crc32 of String, add crc32c(io) to read all of a stream, add optimized open(crc32c, filename), make IOBuffer checksums consistent with other streams
* use crc32c block size of 8192*3, matching the underling C library
* optimized IOBuffer crc32c
