New feature: Synchronize text sent to panes

[dantepippi]

Creating a new keybinding "s" on the Pane mode. When sync is enabled text will be sent to all terminals on the current tab.

Closes #302

[khs26]

Looks great!

I don't think it needs addressing as part of this PR, but I think there are a couple of future extensions - could you create issues for them?

1. Controlling which panes in a tab are in sync mode - this could be particularly useful if one of the panes is a plugin, which wouldn't expect to handle the same input as a regular pane.
2. Highlighting which panes are in sync mode (with a green border, like the active pane).

I particularly like that you've considered the UI by adding the "Sync" label to the tab.

[a-kenji]

Thank you, this looks great!
The default keybindings are now solely defined under /assets/config/default.yaml

[dantepippi]

Looks great!
Thanks for the feedback and taking your time to review my code!

I don't think it needs addressing as part of this PR, but I think there are a couple of future extensions - could you create issues for them?

1. Controlling which panes in a tab are in sync mode - this could be particularly useful if one of the panes is a plugin, which wouldn't expect to handle the same input as a regular pane.

So far I don't replicate the text on plugin panes, only to regular panes. How do you imagine the UI for selecting which panes are in sync? I think being able to sync all panes at once is a nice feature and should also be a choice.

2. Highlighting which panes are in sync mode (with a green border, like the active pane).

I particularly like that you've considered the UI by adding the "Sync" label to the tab.

[dantepippi]

Thank you, this looks great!
The default keybindings are now solely defined under /assets/config/default.yaml

I have updated the code to reflect this change. Thank you for bringing it up.

[TheLostLambda]

Hey @dantepippi! This is a super sick change that's got great code and adds a great feature! Thanks for fixing the merge conflicts!

I'll merge this now and add it to the changelog for you 🙂

Thanks for the awesome PR!