Add a `pipe` method

[williambdean]

Think that it could be pretty convenient to add a pipe method. Any thoughts? I can create a PR if it makes sense

from pypika import Query
from pypika.queries import QueryBuilder


def filter_to_desired_rows(query: QueryBuilder, values_to_select) -> QueryBuilder:
    ...

def aggregated_statistics(query: QueryBuilder, groups) -> QueryBuilder: 
    ...
    

initial_query = Query.from_("my_table")
query = (
    initial_query
    .pipe(filter_to_desired_rows, values_to_select=...)
    .pipe(aggregated_statistics, groups=...)
)