[documentation] Playground to support selecting ts-blank-space version

[acutmore]

Currently the version of typescript and ts-blank-space in the playground is static, they are bundled in at build time. This reduces the utility of the playground as a means to demonstrate specific bugs, or to compare versions.

The playground could allow selecting the version of ts-blank-space and typescript to use. The simplest way would be only having url parameters, a better solution would be a dropdown menu.

Once a package version is selected it can be loaded via an npm cdn such as esm.sh.