worktree: support push: false

[pmrowla]

• ❗ 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. 🙏

Follow up to #8578.
Related to #8464.

• Moves worktree push/fetch logic into dvc.repo.worktree
• Disables pushing dvc import data to worktree remotes
• Disables pushing push: false data to worktree remotes

[pmrowla]

This does not address any of the other worktree push/fetch issues (i.e. reporting that all files are always fetched or pushed/lack of progress bars)

[codecov]

Codecov Report

Base: 94.31% // Head: 94.27% // Decreases project coverage by -0.03% ⚠️

Coverage data is based on head (e2d7841) compared to base (a33bbc9).
Patch coverage: 12.28% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8581      +/-   ##
==========================================
- Coverage   94.31%   94.27%   -0.04%     
==========================================
  Files         430      431       +1     
  Lines       32904    32919      +15     
  Branches     4603     4605       +2     
==========================================
+ Hits        31035    31036       +1     
- Misses       1447     1461      +14     
  Partials      422      422              

Impacted Files	Coverage Δ
dvc/repo/index.py	95.08% <ø> (ø)
dvc/repo/worktree.py	7.54% <7.54%> (ø)
dvc/repo/push.py	58.82% <50.00%> (+28.05%)	⬆️
dvc/repo/fetch.py	77.96% <100.00%> (+8.26%)	⬆️
tests/unit/repo/experiments/conftest.py	88.67% <0.00%> (-5.67%)	⬇️

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[dberenbaum]

Added a checkbox to #8464 for reporting correctly what's been pushed.

[jorgeorpinel]

Hi. From #8578 (comment):

Besides updating the cmd refs, should we recommend this by default when building pipelines?

Context: https://discord.com/channels/485586884165107732/1047778499999576084/1048151267190509600

Cc @dberenbaum WDYT

[jorgeorpinel]

I guess the basics of this are also being documented in iterative/dvc.org#4142...