Pr one workspace per tab

[alan412]

I haven't taken it through all the PR checklist because I found that it failed and when I tried it on main it failed there as well. But since this is pretty simple I am putting it up there for you to start looking at and when we fix the problem in main, it should fix it here as well.

Fixes #283

[lizlooney]

I found a problem where the blocks (or the workspace) shift up and to the left.
Steps to reproduce:

1. Create a new project (or use one if you already have one)
2. The Robot blocks look like this.

Notice that there is a 20 pixel gap between the upper left corner of the workspace and the upper left corner of the mrc_mechanism_component_holder block.
3. Click on the tab for Teleop.
4. Click on the tab for Robot.
Now it looks like this:

Notice that there is no gap now.

[lizlooney]

I found a problem where modules aren't saved.
Steps to reproduce:

1. Create a new project (or use one if you already have one)
2. In Robot, add a comment block to the init method.
3. Click on the tab for Teleop.
4. I did not see the message "Save completed successfully."
5. Refresh the browser.
6. The comment block that I'd added to the init method is gone.

[alan412]

I found a problem where the blocks (or the workspace) shift up and to the left. Steps to reproduce:

Wow, that was something. It turns out that it was a problem in BlocklyComponent. I have the problem gone, but I'll admit that I don't understand why the double RAF (requestAnimationFrame) is needed. But I know that if I remove it the problem comes back....

[alan412]

I found a problem where modules aren't saved. Steps to reproduce:
Fixed

[alan412]

Verified that this also fixes #302

[alan412]

Verified this also fixes #301