ICU-20233 tool: improvements to commit checker for CLDR

ICU-20233 tool: improvements to commit checker for CLDR

- improve checks for CLDR resolutions
- update batch fetch from 50 to 100
- do not show no-commit tickets under illegal-state
- add navigation
- use numeric IDs for status, resolution, types with constants
 (S_, R_, I_)

fix bugs from CLDR-14224
- do not show not-in-query issues as open
- cache single-issue queries
- give information on each problem as to what it is
- put 'review' in a separate section (not counted in Problems)
- more detailed fix info under each issue

- fix section headings, always show component, add nocopyright option
- sort open issues by componnent
- sort the 'review' list

ICU-20444:
- exclude (via git-cherry) any commits already cherry picked to the branch.
- used a workaround to https://github.com/gitpython-developers/GitPython/issues/846
that seemed to work well,
- warn about issues with excluded commits

CLDR-14524:
- Exclude "Obsolete" from requiring commits