recude package sizes #87

installing @codspeed/core currently takes up 5MB of space on disk, which can be reduced quite a bit

https://npmgraph.js.org/?q=@codspeed/core

• axios can be replaced with just fetch, or if mroe complex utilities are needed ky or xior can also work
  • this alone would reduce the install size by 3MB
• find-up can be replaced with empathic, which is smaller and faster
• the packages is currently publishing both CJS and ESM files, along with source maps for both the code and types.
  • node 20.12+ supports require(esm), so you could drop the CJS build if you drop support for versions below it
    • this would remove 0.5MB
  • source maps are generally not necessary if you don't minify the packaged code, and not-minified code without source maps has the best size-to-benefit ratio out of the possibilities
    • this would remove 1MB

all in all i think core could be brought down to about 1/9th of the original size

i would be up for helping with this if you want!