Implement storing runtime state in repo level Git config (#295)

* Add initial impl of storinig state in Git config

* Drop test for find_project_root

* 🚑🐛 Fix all existing tests to match new reality

* 🐛 Fix final path construction in load_config

* 🎨 Validate input in from_git_rev_read function

* 🎨 Move conf path from global scope to CherryPicker

* 🎨 Use Enum for ALLOWED_STATES

* 🎨 Make check_output line shorter

* 🐛 Improve error processing in from_git_rev_read

* ✅🎨 Add tests for from_git_rev_read

* ✅ Add tests for low-level state management

* 🚑 Refer to set_paused_state correctly

* 🚑 Fix set_paused_state method args

* ✅ Test paused flow

* ✅ Cover a test case with unknown sha and fs path

* ✅ Test find_config w/o Git

* ✅ Add tests for two-stage methods

* 🎨 Drop unused fixtures from test_start_end_states

* ✅ Add tests for cleanup_branch

* ✅ Add cherry-pick fail test

* ✅ Add cherry-pick success test

* ✅ Add get_state_and_verify fail test

* ✅ Add push_to_remote tests

* ✅ Add backport test with no branch

* 🐛 Interrupt cherry-pick loop on no-push

* 🐛 Ignore missing config pointer on wipe

* ✅ Cover backport method with tests

* ✅ Cover ``--continue`` with tests

* 🎨 Improve test_backport_pause_and_continue

* 🎨 Use raw-string for regex

* ✅ Cover ``--abort`` with tests

* 🎨 Store all states in Enum structure

* 🔥 Drop garbage comments

* 🎨 Use match instead of message in pytest.raises

* f-stringify concatenation in tests

Co-Authored-By: webknjaz <[email protected]>

* 📝💡 Add change notes

Author: webknjaz