Merge branch 'PR/strv-prefix' of https://github.com/karelzak/util-linux-work

* 'PR/strv-prefix' of https://github.com/karelzak/util-linux-work:
  lib/strutils: add ul_ prefix to strrep() and strrem() functions
  lib/strutils: add ul_ prefix to split() function
  lib/strutils: add ul_ prefix to strappend() functions
  lib/strutils: add ul_ prefix to strconcat() functions
  lib/strutils: add ul_ prefix to startswith() and endswith()
  lib/strv: use ul_ prefix for strv functions