add a comment about group_vars/all purpose
set python interpreter in group_vars/all
add a list of utility packages

See ticket:3036
remove outdated notes
add bootstrap related files

* bootstrap is the main script to run
* bootstrap.yml is the playbook that does the actual job

(This is still work in progress, see bootstrap.yml for comments)
create all users in one place

* rename 'admin_users' tasks to just 'users'
* move service account creation from 'bootstrap.yml' to the above
  mentioned task list
slightly change the way sudoers are ensured

* make sure '#includedir ...' is present
* do not use template (we do not need it atm) and use the file verbatim
* remove the corresponding part from bootstrap.yml
move notes from bootstrap.yml to docs/ansible-todo.txt

* related to the crontask
do not install python

* python2 is installed as a dependency for ansible and is taken care of
  in 'bootstrap.yml' playbook
unify package installation

* install all mandatory packages
* do not install sudo separately (though this can be kept just to be
  sure)
* install all utility packages
* remove the functionality from 'bootstrap.yml'

Fixes ticket:3036
run site.yml during bootstrap

* supply '-u root' as otherwise it will use current user
update bootstrap

* change comments to not include -k
* use -e
* require a hostpattern and pass it with -l
* don't exec the first ansible command (which skips the second)
fix usage
Merge sa2ajj/buildbot-infra:bootstrap (PR #12)