Renaming items and adding Three-Way Frequencies and Pivot-table(summaries) dialogs in Two/Three Variables sub-menu.

[Vitalis95]

Fixes #7259
@rdstern @shadrackkibet, in this PR which affects Two/Three variables sub-menu;
Renames Frequencies to Two-way Frequencies and also adds Three-way Frequencies.
Renames pivot table to Pivot-Table (Frequencies) and also adds Pivot-Table (Summaries)
Also, here is updated database screenshot.

[rdstern]

@Vitalis95 this is almost there, and promising.
@Ivanluv has been working on the Pivot Table that is currently in the (now defunct) 3-way. I think that is approved and merged, or just about ready.
So delete Pivot Table (Frequencies)
Change Pivot Table (Summary) to just Pivot Table.
Check whether it looks better if there is a line above Pivot Table. If so, add a horizontal line just above Pivot Table - which is a bit different. That would make it stand out.
Make sure the Pivot table calls @Ivanluv new dialogue eventually.

Note also that as soon as it is ready, the Correlations option will call the new correlations dialogue you have been working on. And the Summarise dialogue will be including the new version with skimr.

[Vitalis95]

@rdstern in this PR
I have added item Add (Merge) Columns... below Reorder Columns and also update the database for Duplicates... to Duplicate Rows... in Prepare menu as requested by @N-thony in #7297
I have also added a horizontal line just above Pivot Table and deleted Pivot Table (Frequencies)

[Vitalis95]

@rdstern, since this PR isn't yet merged, I have changed the menu item Data Object to Data Book, this partially fixes #7350 . I will add the Original Label control in separate PR.
Also, I have updated the label in the database

[rdstern]

@Vitalis95 that's great. Is it the same pull request where you might add Add (Merge) Columns to the prepare > data frame menu, just after Reorder Columns? See 7029. It is another copy of the same dialogue that is currently in Options by Context > Prepare. @N-thony has a pull request that I've just approved.

[Vitalis95]

@rdstern in this PR I have added item Add (Merge) Columns... below Reorder Columns and also update the database for Duplicates... to Duplicate Rows... in Prepare menu as requested by @N-thony in #7297 I have also added a horizontal line just above Pivot Table and deleted Pivot Table (Frequencies)

@rdstern I have added that dialog in this PR below Reorder Columns. Have a look at it, thanks

[Vitalis95]

@rdstern @derekagorhom @lloyddewit , I have changed dialog name in Prepare>CheckData>Duplicates to Duplicate Rows as suggested in PR #7305
I had Changed the menu item to Duplicate Rows in this PR

[rdstern]

@Vitalis95 that's looking good. Great. Good with @lloyddewit or @shadrackkibet to get it merged