Add an on-demand unload tab feature

[bbondy]

Some requests for it for lower memory use. Some people dislike the feature though so we should be careful about how we implelment and do it as an option.

[ghost]

The best idea. Make things optional, so it does not get in the users way. People who want that feature can activate it, the ones who do not want it leave it alone.

[bridiver]

Sharing the tab between windows will also cut down on memory. Right now we have a process/tab/window for pinned tabs.

[luixxiul]

Fully implemented with #1795 or is there anything which it does not cover?

[cezaraugusto]

/cc @bbondy @bridiver for further info about @luixxiul question

[bbondy]

I think a right click context menu to unload tab would remain here.

[bbondy]

Here is how it works on Vivaldi, there are 2 items, one for active tab and one for all tabs except this one.

Also added this at the page tab level would be good for the tab page context menu.

[cndouglas]

Related: #6251 (Automatically suspend inactive tabs)

[petemill]

We have in #13118 (and 0.21.x) a tab context menu item now named 'Discard Tab' which allows a user to manually destroy the tab's contents and reload it when the tab is made active again. However, Brave has to be running with the Debug menu on to allow this option currently.

[bsclifton]

Closing as wontfix since we won't be able to address this with browser-laptop. However, with Brave Core, an extension such as The Great Suspender could be used