[Feature Request] [Winbar] Better mouse interaction

[ofseed]

If I click a #2 in a winbar like this

it will open #2 split like this

But I think maybe in most situations, I just want #2 to replace #1 like this

Perhaps it is possible to assign different functions to the left and right mouse buttons so that the left button replaces the current terminal, and the right button opens the second terminal split.

[akinsho]

@ofseed I'd be happy to take a PR that allowed customising the functions used when clicking the winbar. The main issue is that there is currently no function in toggleterm that allows you to replace the current window terminal so that would need to be created