[IMPR] Improvements for makecat.py
[IMPR] Improvements for makecat.py

- use "tocheck" DequeGenerator as MakeCatBot attribute
- implement "summary" as as MakeCatBot attribute and change methods
  arguments accordingly
- implement "generator" as as MakeCatBot attribute
- implement init_page() previously done in asktoadd()
  to add redirect targets to check list
- implement skip_page() to skip not existent page
  previously skipped in last main for statement
- rename asktoadd to treat_page and assign current_page to pl
- let the bot run by in behaviour

7th step detached from Id7ca3461d for easier reviewing

Bug: T192706
Change-Id: Ib3249fd2b6b19c974e0ff3be1e0ed960396612f7

wikimedia/pywikibot-core,wikimedia/pywikibot-core