[DOCUMENTATION] - improve searchability and visibility of Regrid instructions

When you search for Regrid on the github page, you end up at the more complex use case, namely regridding entire models or packages.

For grid-level applications, the first relevant search result with Regrid in the title appears much further down the list:
https://deltares.github.io/imod-python/user-guide/08-regridding.html

Even on that page, the focus quickly shifts to regridding models. The page does start with a paragraph about working with individual scripts, and then states:

“More information on the available regridding methods can be found in the xugrid documentation
[https://deltares.github.io/xugrid/user_guide.html”](https://deltares.github.io/xugrid/user_guide.html”)

This link does not quite lead to the most relevant page.

Suggestion: could this link be changed to
https://deltares.github.io/xugrid/examples/regridder_overview.html ?

What you actually want users to find in the iMOD Python documentation is this paragraph:
https://deltares.github.io/imod-python/faq/how-do-i/index.html#change-cellsize-and-extent

Suggestion: if the word “regrid” is included in the paragraph title, it will also show up in search results.

Proposed title:
“Change cellsize and/or extent (Regridding)”

In addition:

• consider adding the 3rd option "BarycentricInterpolator"
• consider adding a list of possible methods with the option "OverlapRegridder"