updated to add OIDC support - Basic

[bmcgonag]

I added the basics to update the build so it will include the basic environment variables for OIDC setup. If this is accepted,a nd works well, I'll work on adding more of the vars for more advanced setup with groups and permissions, etc. But for now, with this, you should setill setup an admin using built in auth so you can adjust OIDC useer perms once created.

[si458]

if you wanted you can do a PR against the offical docker image 👍 https://github.com/Ylianst/MeshCentral/tree/master/docker