Parameterize # of GameServer Creation/Deletion

[nottagg]

Fixes #157

Felt like a pretty similar change to #419, so I figured I would take a look.

• The max number of servers to add/delete are now parameters in gameserverbuild_controller.go
• config.go was created, moving the config struct from main.go to its own file inside controllers
• This allows any controller to now accept the config struct and make use of env variables
• gameserverbuild_controller.go constructor now utilizes the config
• Changing the default values of 20 can be done during deployments via env variables

I did not make these env variables in the makefile. I could refactor the PR to do so if desired, but I figured it would be better to wait on a change fixing the dropped double quotes I faced in #419 . Unlike that one, these wouldn't require an int and string variable so it would be a little prettier. Combining these max add/delete into one variable may also be a refactor to consider. Thanks!

[nottagg]

@microsoft-github-policy-service agree company="Microsoft"

[dgkanatsios]

hey @nottagg, thanks for the PR! A couple of changes and we would be good to go!

[nottagg]

Hey @dgkanatsios,

This is ready for review. I've also updated the original description to better reflect the changes made. I think things should further be refactored to eventually separate the type files (port_registry, config) from the controller folder into their own folder. But I won't include that onto this PR

[dgkanatsios]

great job @nottagg, thank you!