cli: improve startup speed

[skshetry]

fsspec callbacks were making us lose 35ms (~207 ms vs 170ms now).
These are now extracted from dvc.progress to dvc.fs._callback.

On main:

$ hyperfine "dvc --help" --warmup 5 --runs 20
Benchmark 1: dvc --help
  Time (mean ± σ):     207.2 ms ±   3.0 ms    [User: 171.2 ms, System: 34.1 ms]
  Range (min … max):   201.8 ms … 214.8 ms    20 runs

vs

On HEAD:

$ hyperfine "dvc --help" --warmup 5 --runs 20
Benchmark 1: dvc --help
  Time (mean ± σ):     171.2 ms ±   2.9 ms    [User: 141.3 ms, System: 28.0 ms]
  Range (min … max):   165.4 ms … 177.7 ms    20 runs

See https://github.com/iterative/dvc/wiki/Debugging,-Profiling-and-Benchmarking-DVC#benchmarking-startup-performance and https://github.com/iterative/dvc/wiki/Debugging,-Profiling-and-Benchmarking-DVC#benchmarking-dvc-commands.

• ❗ I have followed the Contributing to DVC checklist.

• 📖 If this PR requires documentation updates, I have created a separate PR (or issue, at least) in dvc.org and linked it here.

Thank you for the contribution - we'll try to review it as soon as possible. 🙏

[skshetry]

From benchmark results on https://github.com/iterative/dvc/runs/4870806079?check_suite_focus=true#step:4:2214 :

-------------------------------------------------------------------------------- benchmark 'test_help---help': 2 tests ---------------------------------------------------------------------------------
Name (time in ms)                        Min                 Max                Mean             StdDev              Median                IQR            Outliers     OPS            Rounds  Iterations
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
test_help---help (NOW)              176.6728 (1.0)      203.3401 (1.0)      186.9370 (1.0)       7.8782 (1.0)      186.3254 (1.0)       9.9555 (1.0)           2;0  5.3494 (1.0)          10           1
test_help---help (0001_4ff64f0)     277.1404 (1.57)     312.2262 (1.54)     292.0010 (1.56)     11.2194 (1.42)     288.2971 (1.55)     12.6845 (1.27)          3;0  3.4246 (0.64)         10           1
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------