Update fastdds formula to 2.0.2

[ThomasDebrunner]

This upgrades the fast-rtps (now called fast-dds) to v2.4.0
This was made in an effort to make the px4-dev install natively on Apple Silicon M1

Additional changes:

• fast dds now depends on foonathan-memory. This adds a formula for that
• fastddsgen (formerly fastrtpsgen) is now its own repository. This adds an explicit formula for this

[TSC21]

We do not support FastDDS 2.4.0. Or we might but this will have to go through extensive testing. Also fastddsgen (2.0.0 and above) only generates code for DDS API, not RTPS API, which we do require (https://github.com/eProsima/Fast-DDS-Gen/releases/tag/v2.0.0).
I would start by making sure we are installing the base version we support (FastDDS 2.0.2 and FastRTPSGen 1.0.4). And as soon as it makes sense we move to newer versions.
Also FastDDSGen will not be required as soon as we move to Micro XRCE-DDS.

[ThomasDebrunner]

@TSC21 Understood! I changed the target version to fastdds 2.0.2 and fastddsgen to 1.0.4
The version changes were trivial here, since the dependency changes cam in with fastdds 2.x

[wyager]

Can this be merged? cf #77