feat: Custom sort orders & support for multiple sort tags.

**Is your feature request related to a problem? Please describe.**

Working with bare repositories + worktrees makes the local branches tab quite useless.
With a bare repo, `git branch` lists all of the remote branches as local.

**Describe the solution you'd like**
I would like to use the following sorts:

`--sort=-worktreepath --sort=-HEAD`, this will list the current worktree first, then all other worktrees, then all other branches which are not checked out in a worktree.

**Describe alternatives you've considered**
Tried looking for config options, this will not work in gitconfig since `branch.sort` is only used by git if `--sort` is not specified (but lazygit always passes `--sort`)

**Additional context**

The other thing that contributes to this problem is that with recency (the default sort) as the default sort, recent branches are not recent in the context of multiple worktrees. Since if I checkout branchA and then branchB in separate worktrees, branchA will not be considered recent from branchB since branchA wasn't checked out recently from branchB's worktree. So it pretty much sorts HEAD then everything else alphabetically, assuming a one-branch-one-worktree workflow.

Example of the sort:

`git branch --sort=-worktreepath --sort=-HEAD`:

```
* trunk
+ c_daemon
1000-add-feedback-to-no-ports-desktop
712-empty-session-and-tunnel-username-prevents-a-successful-ssh-in-the-desktop-app
713-the-desktop-app-is-stuck-on-a-loading-screen-when-a-hung-session-occurs
714-fix-settings-screen-shows-a-grey-box
731-buggy-nav-bar-see-video-below
733-organize-config-screen-fields-into-a-2-column-layout
754-make-sure-the-dashboard-page-reloads-to-show-the-profiles-after-initial-sync
775-profile-boolean-fields-resorts-to-the-default-value-when-the-submit-button-is-pressed-sometimes
... etc.
```

Where trunk is the current worktree, and c_daemon is the only other worktree.

Happy to work on a PR for this over the weekend.