perf: quick validation of enviroment on activating commands

[ruben-arts]

This pr will add a hash of the lock file to the EnvironmentFile (.pixi/envs/default/conda-meta/pixi)

It will look like this:

{
  "manifest_path": "/home/rarts/dev/pixi/pixi.toml",
  "environment_name": "default",
  "pixi_version": "0.34.0",
  "environment_lock_file_hash": "4f36ee620f10329d"
}

And that hash will be compared with the current lockfile on pixi run pixi shell pixi shell-hook.

Profile result:

❯ hyperfine "pixi run echo" "old-pixi run echo"
Benchmark 1: pixi run echo
  Time (mean ± σ):     381.6 ms ±  22.1 ms    [User: 193.8 ms, System: 246.3 ms]
  Range (min … max):   344.5 ms … 414.3 ms    10 runs
 
Benchmark 2: old-pixi run echo
  Time (mean ± σ):     868.2 ms ±  58.2 ms    [User: 480.0 ms, System: 557.0 ms]
  Range (min … max):   791.1 ms … 950.8 ms    10 runs
 
Summary
  pixi run echo ran
    2.28 ± 0.20 times faster than old-pixi run echo