Osidb-bindings

Added
- add `next()`, `prev()` and `iterator()` methods for paginated
responses to make page browsing easier
- require exported `BUGZILLA_API_KEY` environment variable for
some session operations which are particulary unsafe (create, update, etc.)
for authentication/authorization against Bugzilla

Changed
- update allowed session operations for each resource

Removed
- remove old aliases for session operations with flaws (eg. `session.retrieve()`,
`session.retrieve_list()`, etc.) in favor of new resource operations
(eg. `session.flaws.retrieve()`, `session.flaws.retrieve_list()`, etc.)

Added
- bring back `session.operation()` as an alias for flaws operations
to prevent breaking changes

Changed
- fix session.status call error

Changed
- add additional resources for queries (affects and trackers),
session now works as `session.resource_name.operation()` instead of
old `session.operation()`

Added
- exported `REQUESTS_CA_BUNDLE` environment variable is now needed
in order to have the kerberos authentication working for instances
of OSIDB which are using this auth

Changed
- change the authentications to token authentication where the token
is obtained either via username/password or kerberos, bindings
handles the token retrieval/renew for the user