Object size limit between host and worker

#### What problem would the feature you're requesting solve? Please describe.
It seems like the Functions host can only handle a maximum object (e.g. blob) size of 2GB. This is because of a CLR limit [as mentioned here](https://stackoverflow.com/questions/1087982/single-objects-still-limited-to-2-gb-in-size-in-clr-4-0).
To have a consistent view on what the acceptable range is, the worker and host need to agree on a commonly supported range of object sizes.

#### Describe the solution you'd like
In the host-init/worker-init messages, the host and worker should exchange the min/max object size they can handle. Based on this, a commonly acceptable range should be agreed upon.

#### Describe alternatives you've considered
n/a

#### Additional context
In the future, if larger objects are to be supported, this limit needs to be implemented so that only those workers are given large objects who can properly support them.