code-gen: support multiple 'viaXxx' in the query builder

[dirkdev98]

This works by intersecting the result of multiple traverses. This guarantees the same 'AND' behaviour as usual. It also works when the 'xxIn' property is already set, by converting it inline to a 'select from values' expression.

Closes #660

[github-actions]

==== Benchmark result ====

Node.js version: 15
Total benchmarks: 15
          Passed: 15
          Failed: 0
-----------
router - github static path              200000  iterations    9110  ns/op
router - github path params              100000  iterations   10066  ns/op
compas validator simple                 5000000  iterations     273  ns/op
yup validator simple                     100000  iterations   14168  ns/op
fastest-validator validator simple     10000000  iterations     107  ns/op
compas validator nested                 1000000  iterations    1481  ns/op
yup validator nested                      20000  iterations   50011  ns/op
fastest-validator validator nested      2000000  iterations     565  ns/op
logger - strings                         500000  iterations    3159  ns/op
logger - objects                         500000  iterations    3851  ns/op
logger - deep objects                    500000  iterations    6210  ns/op
uuid                                    5000000  iterations     394  ns/op
uuid.isValid                           10000000  iterations     144  ns/op
isNil                                 500000000  iterations       0  ns/op
isPlainObject                         100000000  iterations      18  ns/op

[github-actions]

==== Benchmark result ====

Node.js version: 14
Total benchmarks: 15
          Passed: 15
          Failed: 0
-----------
router - github static path              200000  iterations    9606  ns/op
router - github path params              100000  iterations   11786  ns/op
compas validator simple                 5000000  iterations     289  ns/op
yup validator simple                     100000  iterations   13865  ns/op
fastest-validator validator simple     10000000  iterations     117  ns/op
compas validator nested                 1000000  iterations    1513  ns/op
yup validator nested                      50000  iterations   46673  ns/op
fastest-validator validator nested      2000000  iterations     583  ns/op
logger - strings                         500000  iterations    3126  ns/op
logger - objects                         500000  iterations    3739  ns/op
logger - deep objects                    200000  iterations    6650  ns/op
uuid                                    2000000  iterations     536  ns/op
uuid.isValid                           10000000  iterations     143  ns/op
isNil                                 500000000  iterations       0  ns/op
isPlainObject                          50000000  iterations      20  ns/op

[github-actions]

==== C8 test coverage ====
Statements: 65.77% ( 24715/37579 )
Branches : 64.85% ( 2725 /4202 )
Functions : 66.8% ( 825 /1235 )
Lines : 65.77% ( 24715 /37579 )