Allow for typecasting in `dynamic_function_fragment`

[akoutmos]

We should allow for optional params to be type casted since TimescaleDB allows for many different type args like in the time_bucket_ng function: https://docs.timescale.com/api/latest/hyperfunctions/time_bucket_ng/#required-arguments

Issue is from this todo: https://github.com/bitfo/timescale/pull/7/files/04432106e4c8709f7d5e122862e649fd36e90cff#diff-6d0e22f3d21d3b1f14d00c23a58aaf6c2f75ead03982637080cde9920c73ebfaR31-R33