Handle naming inconsistencies between SQL, DataFrame API and struct names

[asfimport]

Currently, we have naming inconsistencies between the different APIs that make it a bit confusing. The typical example atm is

df.where().to_plan?.explain() shows a "Selection" in the plan when "Selection" in SQL and many other query languages is a projection, not a filter.

Other examples:

name: Selection
SQL: WHERE
DF: filter

name: Aggregation
SQL: GROUP BY
DF: aggregate

name: Projection
SQL: SELECT
DF: select,select_columns

I suggest that we align them with a common notation, preferably aligned with other more common query languages.

I am assigning this to you @andygrove as you are probably the only person that can take a decision on this.

Reporter: Jorge Leitão / @jorgecarleitao
Assignee: Andy Grove / @andygrove

PRs and other links:

• GitHub Pull Request #7998

_{Note: This issue was originally created as ARROW-9788. Please see the migration documentation for further details.}

[asfimport]

Andy Grove / @andygrove:
Issue resolved by pull request 7998
#7998