also tweak some names and types

* Adopt TerminalVirtualProcess for Custom task execution

* Update Custom task execution API to return TerminalVirtualProcess in callback

This also required the addtion of a start on the virtual terminal process

* Clarify start API

Fixes #76492

For #76489

* Adding support for TaskProvider.resolveTask.

* Reorganize task grouping and resolution async code for readability.

* Made small changes and implmented resolveTask for gulp

fixes #75881

See #75278

For #72155

This allows  us to potentially change the resource root per webview

Part of https://github.com/microsoft/vscode-remote-release/issues/757

Part of #75091

Fixes #72155

Adds a constant to the api that tracks the root path for resources inside of webviews. This is required because we will not be able to use `vscode-resource:` uris on the web. Our current approach is to rewrite the html we are given but there are almost certainly going to be cases where we don't get this quite right.

Adopts the new api for the markdown preview

Part of #75091

For #74846

Migrates from using the heap service to have an explicit lifecycle

Part of #75091

Fixes #75278

debt - decouple webviews from code insets, move things to /browser/-layer, change inset api proposal to push style, re #66418