Credit: [@Musisimaru](https://gitlab.com/Musisimaru) (originally
    introduced in
    [!229](https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/merge_requests/229))

This is a copy paste of the code contributed by Mussimaru in
https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/merge_requests/229
This code doesn't compile, but I wanted to include it as a record that
he's done most of the work.

This reverts commit 058963f9.

This commit limits when is it possilbe to run a command.
Most of the commands should not be run if the extension
isn't in a valid state (e.g. no repository or token)

Signed-off-by: NTakuya Noguchi <takninnovationresearch@gmail.com>

Signed-off-by: NTakuya Noguchi <takninnovationresearch@gmail.com>