js: Remove some unused code from the stack form
templates: Fix the package checkbox alignment
models: Add a Stack.users<->User.stacks relationship
stacks: Set the default owner to the user that created the stack
stacks: Add user/group validation
stacks: Update the Stack.users relationship when saving
templates: Add users and groups to the new stack form
tests: Edit the stack description too
tests: Try adding a stack without group privs
tests: Try adding a stack without user privs
tests: Add a stack with proper user privs
tests: Edit a stack with proper group privs
tests: Render our new stack form for 99% stacks.py coverage
tests: Update our User sql_statements counts for the new stack relationship