Lite Terminal shell integration improvements

[isc-bsaviano]

• Adopts Shell integration nonce unavailable in unknown shells and Pseudoterminal-based extension terminals microsoft/vscode#190253 so commands can be re-run without user confirmation
• Allow pasting of multi-line content into READ prompts
• Work around VS Code bug to allow re-running of multi-line commands
• Correctly capture command output in shell integration
• Fix some edge cases where the cursor and text could get out of sync

I'm opening this as a draft even though the code is ready for review because I think it should be merged just before a 3.2.0 release. This PR bumps the minimum supported VS Code version to 1.104.0 which we probably don't want to get in a 3.0.7 release if we need one.

[gjsjohnmurray]

Shall we merge this and prepare a 3.2.0 release for next Monday?

[isc-bsaviano]

I would like to wait for the early October VS Code because it should finalize the TerminalCompletionProvider. I need to add a little code to this extension to enable the Language Server to provide completions in terminals. I could add that code now and do a separate PR in a future release if it needs modification, but I would prefer to include it in 3.2.0. I will check with the VS Code team that that API is still on track for finalization.

[isc-bsaviano]

Marking as ready for review because at this point 3.2.0 will be the next version. Whether we release that before or after the next VS Code version is still TBD.

[gjsjohnmurray]

LGTM