* common/fdlimit: cap on MacOS file limits, fixes#18994
* common/fdlimit: fix Maximum-check to respect OPEN_MAX
* common/fdlimit: return error if OPEN_MAX is exceeded in Raise()
* common/fdlimit: goimports
* common/fdlimit: check value after setting fdlimit
* common/fdlimit: make comment a bit more descriptive
* cmd/utils: make fdlimit happy path a bit cleaner
* common/fdlimit: Move fdlimit files to separate package
When go-ethereum is used as a library the calling program need to set
the FD limit.
This commit extract fdlimit files to a separate package so it can be
used outside of go-ethereum.
* common/fdlimit: Remove FdLimit from functions signature
* common/fdlimit: Rename fdlimit functions
