Stefan Holderbach a0cecf7658
Move format duration/filesize back into core (#9978)
# Description
Those two commands are very complementary to `into duration` and `into
filesize` when you want to coerce a particular string output.

This keeps the old `format` command with its separate formatting syntax
still in `nu-cmd-extra`.

# User-Facing Changes
`format filesize` is back accessible with the default build. The new
`format duration` command is also available to everybody

# Tests + Formatting
2023-08-11 06:01:47 +12:00
..