New Tab Opens Next to Current Tab

[monperrus]

Expected Behavior:
When a user opens a new tab in Terminator, it should open directly next to the currently active tab, allowing for easier navigation and organization of tabs. This behavior would enable users to maintain a logical flow of their
terminal sessions.

Actual Behavior:
Currently, when a user opens a new tab, it opens at the end of the tab list. This can disrupt the workflow, especially when users are managing multiple related tasks across several
tabs.

Steps to Reproduce:

1. Open Terminator.
2. Open multiple tabs (e.g., Tab 1, Tab 2, Tab 3).
3. Click on Tab 2 to make it the active tab.
4. Use the keyboard shortcut (e.g., Ctrl+Shift+T) or the menu option to open a new tab.

Observed Result:
The new tab (Tab 4) opens at the end of the tab list, after Tab 3.

Expected Result:
The new tab should open immediately to the right of Tab 2, resulting in the tab order being: Tab 1, Tab 2, New Tab (Tab 4), Tab 3.