audit rmw_fastrtps_cpp

[mikaelarguedas]

meta-ticket, follow-up of #107 :
includes

• audit calls to malloc and new and replace them if appropriate
• audit any function call that can throw and either catch them or replace them
• remove magic numbers: partially captured in Magic_numbers in calculateMaxSerializedSize #72
• remove irrelevant todos
• fix cleanup on all failure scenarios: catprued in Fix clean up on failure in rmw_* functions #33
• split functions.cpp in digestable files: done in Refactor functions cpp #135
• replace assert with return with proper value and error messages
• audit sanity checks to make sure they make sense (e.g. use rcutils logging #138 (comment))

(feel free to complete this list I likely missed a few important items)

[mikaelarguedas]

refactor performed, audit not done yet

[clalancette]

Given the sheer age of this, I'm going to close it out. All of the code can probably use an audit, but rmw_fastrtps is so different from when this is opened that I don't think the same things apply anymore. If you disagree, feel free to reopen.