Add translation to comparison expressions

[toppyy]

Related to #172

Sketch of using introducing the use comparison expressions in duckplyr. See related PR in duckdb-r duckdb/duckdb-r#457

[krlmlr]

duckdb 1.1.1 is on CRAN now, and has the necessary additions. Would you like to take another stab?

• Can you please style the code with styler? (Good after chore: Apply styler #281, needs Adapt to single indent semantics in style guide r-lib/styler#1235 to avoid noise)
• map_xxx() or map() are better than sapply()
• When comparing types, should we use class() ?

[toppyy]

Thanks! I'll take another stab with these comments in mind.