Keep Web Shell and backing ConsoleShell PTY widths in sync

[notthetup]

Currently, we use xterm and xterm's add-on fit to paint the web-based terminal and resize it when the webpage is resized.

However, that changes the width of the terminal and we need to let the PTY know that this has happened so it can re-render.

Now, the problem is we use a single PTY to serve multiple web shells, so there is no way we can keep all those web shells in sync while they resize.

So we need to explore of ways we can resize the web shell without changing it's width.