CLN,ENH: replace dataframe vs get dataframe() and set_dataframe()

[jcrivenaes]

Since .dataframe property now is deprecated, replace all instances in both code and tests with get_dataframe() and set_dataframe().

Also deprecated dataframe() method in RegularSurface.

The get_dataframe() in Points/Polygons/Wells will have an option to use copy=False which will return a view of the Pandas dataframe instead of a copy, which will be faster and more memory efficient, but also more vulnerable if the dataframe is manipulated directly.

[codecov-commenter]

Codecov Report

Attention: 33 lines in your changes are missing coverage. Please review.

Comparison is base (89b6082) 80.15% compared to head (164fb45) 80.16%.

Files	Patch %	Lines
src/xtgeo/xyz/points.py	38.46%	5 Missing and 3 partials :warning:
src/xtgeo/xyz/_xyz.py	69.56%	4 Missing and 3 partials :warning:
src/xtgeo/well/_well_oper.py	82.75%	3 Missing and 2 partials :warning:
src/xtgeo/plot/xsection.py	66.66%	4 Missing :warning:
src/xtgeo/plot/xtmap.py	50.00%	2 Missing :warning:
src/xtgeo/well/_wellmarkers.py	91.30%	0 Missing and 2 partials :warning:
src/xtgeo/grid3d/_grid_wellzone.py	85.71%	0 Missing and 1 partial :warning:
src/xtgeo/surface/_regsurf_gridding.py	0.00%	1 Missing :warning:
src/xtgeo/well/well1.py	96.87%	0 Missing and 1 partial :warning:
src/xtgeo/xyz/_xyz_io.py	66.66%	0 Missing and 1 partial :warning:
... and 1 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1112 +/- ## ======================================= Coverage 80.15% 80.16% ======================================= Files 96 96 Lines 13534 13580 +46 Branches 2195 2196 +1 ======================================= + Hits 10848 10886 +38 - Misses 1953 1961 +8 Partials 733 733 ```

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