[TabLayout] Margin for each tab item

Nobody has claimed this yet.

Currenlty you can not change a Tab item from the TabLayout from the styles, you have to do some hacky thing like:

The issue is when you want to change the tab background shape into something like:

But since this is not possible from the styles it will appear like this since:

# Possible Solution
One atribute `tab_margin_start` and each margin for each item maybe?

# Current hacky solution
Hacky programaticaly solution [source](https://spotandroid.com/2016/11/02/how-to-add-margins-between-tabs-in-tablayout/):

```kotlin
for(int i=0; i < mTabLayout.getTabCount(); i++) {
View tab = ((ViewGroup) mTabLayout.getChildAt(0)).getChildAt(i);
ViewGroup.MarginLayoutParams p = (ViewGroup.MarginLayoutParams) tab.getLayoutParams();
p.setMargins(0, 0, 50, 0);
tab.requestLayout();
}
```

Start by reading the TabLayout implementation and its tab item layout handling. Compare the requested per-item margins with the current styling behavior and the documented programmatic workaround. Done means margins can be configured through supported styling or attributes without that workaround, with behavior verified for multiple tabs.

Written by the indexing model from the issue text.