Add generic context option for custom function resolution

[michaelbridge]

Context

Enable pass-through of generic parameters to underlying custom functions via context option. Further discussion here.

How did you test your changes?

Added tests; ran npm run test

Types of changes

• [ ] Breaking change (a fix or a feature because of which an existing functionality doesn't work as expected anymore)
• [x] New feature or improvement (a non-breaking change that adds functionality)
• [ ] Bug fix (a non-breaking change that fixes an issue)
• [ ] Additional language file, or a change to an existing language file (translations)
• [ ] Change to the documentation

Related issues:

1. Fixes #808

Checklist:

• [x] I have reviewed the guidelines about Contributing to HyperFormula and I confirm that my code follows the code style of this project.
• [x] I have signed the Contributor License Agreement.
• [x] My change is compliant with the OpenDocument standard.
• [x] My change is compatible with Microsoft Excel.
• [x] My change is compatible with Google Sheets.
• [x] I described my changes in the CHANGELOG.md file.
• [ ] My changes require a documentation update.
• [ ] My changes require a migration guide.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.36%. Comparing base (48bceb0) to head (0d30593).

Additional details and impacted files

[](https://app.codecov.io/gh/handsontable/hyperformula/pull/1398?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=handsontable) ```diff @@ Coverage Diff @@ ## develop #1398 +/- ## ======================================== Coverage 97.36% 97.36% ======================================== Files 169 169 Lines 14421 14422 +1 Branches 3100 3100 ======================================== + Hits 14041 14042 +1 Misses 377 377 Partials 3 3 ``` | [Files](https://app.codecov.io/gh/handsontable/hyperformula/pull/1398?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=handsontable) | Coverage Δ | | |---|---|---| | [src/Config.ts](https://app.codecov.io/gh/handsontable/hyperformula/pull/1398?src=pr&el=tree&filepath=src%2FConfig.ts&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=handsontable#diff-c3JjL0NvbmZpZy50cw==) | `98.01% <100.00%> (+0.01%)` | :arrow_up: |

[sequba]

Merging to temporary branch feature/issue-1396 to resolve conflicts with develop