Allow for single organization

[TylerMizuyabu]

Created a new module and modified the github foundations module to allow for a single organization approach to work

The changes:

• enterprise_organization module created to separate org creation from github foundation repository setup
• removed variables and code from github foundation repository that sets up the github foundation enterprise organization

Other changes:

• removed branch protection in favor of rulesets
• formatted everything with terraform fmt
• removed useless variable from ruleset module