The VS Code team recently retired a deprecated domain used for VS Code
downloads. This breaks update-vscode.sh and customized package
installations (such as used by home-manager). The new domain name is the
one preferred by the VS Code team, as stated in this GitHub issue:
https://github.com/microsoft/vscode/issues/119822
Split up the vscode update.sh into separate vscode/vscodium update
scripts. Recently the versions of vscode and vscodium have diverged (see
VSCodium/vscodium#501), meaning that the updates for one package fail
while the other succeeds. This PR splits up the update scripts so that
one can be run with out the other and vice-versa.
