Feature/tz features

[AlexAtkinson]

Introduces:

TimezoneHandler

Uses libc to retrieve the TZ from the system for each file.
CHANGE: Re-purposes %Z to introduce abbreviations in output.

Note

%Z duplicated %:z, which persists.

# Old ~~~~~
eza --time-style +"%FT%H:%M %Z" -l
drwxrwxr-x    - alex 2026-02-28T19:12 -05:00 benches
# New ~~~~~
cargo run -- --time-style +"%FT%H:%M %Z" -l
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.08s
Running `target/debug/eza --time-style '+%FT%H:%M %Z' -l`
drwxrwxr-x    - alex 2026-02-28T19:12 EST benches

UTC Argument

Adds the --utc argument to output timestamps in UTC, aligning with date, ls.

Note

Unfortunately -u was previously committed for the long view option -u, --accessed.
👀 LMK if this can be reallocated to the --utc argument.