[FEA] Add a sentinel `constexpr` value to denote `INVALID_INDEX`

[ttnghia]

Currently, various cudf APIs need to use a special constant to denote an invalid row index for certain operations. However, there is not any guideline on what constant should be used to mark an invalid index row. Therefore, different APIs implement their own INVALID_INDEX constant.

For example:

• lists/explode.cu: constexpr size_type InvalidIndex = -1;
• detail/scatter.cuh: std::numeric_limits<size_type>::lowest() is used
• lists/extract.cu: std::numeric_limits<size_type>::max() is used

And maybe more. As such, the constants used for INVALID_INDEX is not agreed across cudf development. We should explicitly add a sentinel constant in some of cudf main header and replace the existing ones with it. By doing so, we can enforce consistency and reduce confusion (why this file uses -1 while other file uses numeric_limit::lowest() or numeric_limit::max()).

[harrism]

If this is added, be sure to add a section to the libcudf DEVELOPER_GUIDE.md as well.

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[github-actions[bot]]

This issue has been labeled inactive-90d due to no recent activity in the past 90 days. Please close this issue if no further response or action is needed. Otherwise, please respond with a comment indicating any updates or changes to the original issue and/or confirm this issue still needs to be addressed.