pyinfra/operations: `git worktree add --force` support

[Pirols]

-- Why is this needed?

Current scenario:

1. During pyinfra deployment: git worktree add /path/to/wk commitish

2. rm -f /path/to/wk happens

3. Deployment is run again, however git worktree add /path/to/wk commitish fails:

   fatal: '../wk' is a missing but already registered worktree; use 'add -f' to override, or 'prune' or 'remove' to clear

   Requiring manual intervention: git worktree prune and even git branch -d wk if the branch was created.

Solution:

Use -f/--force (i.e. force) to avoid the failure entirely.