renaming variables and functions:
formulaArray -> FormulaDependency
formulaArrayCache -> FormulaDependenciesMap
formulaObject -> FormulaCellInfo
formulaObjects -> FormulaCellInfoMap

removed FormulaDependenciesMap (formulaArrayCache) - it is only useful for cut-paste operation or large duplicate functions addition - which is not in scope of this PR.

Useful undo/redo test cases:

1. delete formula > undo > change dependency
2. delete formula > undo > change dependency in another sheet
3. delete dependency > undo > change dependency > observe chain formulas
4. replace formula with fill handle > undo > change dependency
5. delete row/col(s) > undo > change dependency
6. inside a NEW sheet: add formula > undo > change old dependency (value object test case)
7. inside a OLD sheet: add formula > undo > change old dependency (null check test case)
8. in a sheet1 - define A1 = 1, B1 = '=A1+10'. fill handle C1 and D1 from B1. do this again in sheet2. modify dependency > it doesn't modify formulas in sheet2.
9. add formula > delete sheet > undo > change dependency