Small tweaks

[isc-bsaviano]

This PR arose during my investigation of #1537 for server-side editing.

• Fire file change events for related documents that were updated by compilation.
• Remove unneeded cache clearing before firing file change events and refresh of server-side class that's open in a low-code editor. VS Code's calling of stat() will cause the file to update in these cases.
• Remove unneeded workspaceState updates from FileSystemProvider. This is a client-side feature.
• Fire file create events when creating files via writeFile()or rename().
• Don't allow rename() to overwrite a file that's marked read-only by source control or due to being deployed.
• Don't allow using client-side "import and compile" commands with server-side files.
• Hide some commands when the active text editor is dirty.

@gjsjohnmurray I've tested this a bunch but I would appreciate you playing with it for a little bit just to make sure it's good.

[gjsjohnmurray]

@isc-bsaviano OK, I have installed the dev VSIX. My usage will likely be exclusively server-side, so that's the scenario I'll be testing.