Fixes #11078 - Substitute find_all_by by where to comply with Rails 4

This commit takes away all instances up to this point of find_all_by to
improve Rails 4 compatibility. They are substituted by .where calls.

Refs #3809 - Style/blocks cop enabled

Fixes #10879 - reported_at column is NOT NULL

Allows for better optimisation of queries on PostgreSQL with
scoped_search.

Fixes #10526 - Support for Cisco POAP

fixes #10861 - Remove unused columns from the hosts table

• Serial - Never really used, probably can be refactored as kernel
  parameters.
• last_freshcheck, source_file_id - left overs from puppet old store
  configs compatibility that we no longer use, I assume no one is using...

Fixes #10409 - Rails 4 compatible changes with Rails 3

Fixes #10793 - rename old class name in taxonomy ignore_types

Fixes #10656 - Prevent audits on counter cache update

Fixes #10713 - improved backtrace logging

• full trace in 500 page in production shows really the full trace
• Foreman::Logging.exception as an unified entry point for exceptions logging
• the backtrace cleaner doesn't delete the plugins
• the orchestration exceptions gets the backtrace covered by logger...

Fixes #7096 - Adds STI to templates

This commit converts Ptables to be just another type of Template so it
gets the same features as ConfigTemplate. ConfigTemplate was renamed to
ProvisioningTemplate to reflect UI and the name under it's commonly known.