Removed a_ prefix on arguments

[JohanBertrand]

Related Issue(s)	https://github.com/nasa/fprime/issues/2492
Has Unit Tests (y/n)	yes
Documentation Included (y/n)	yes

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Change Description

Removed the prefix _a previously added in https://github.com/nasa/fprime/pull/2482

Changes:

• Changed public variables of Fw/FilePacket and Svc/FileDownlink to PRIVATE variables

• Changed public variable name to private variable m_name in STest/STest/Rule/Rule.hpp

• Remove object initializion using public variable list in Svc/FileDownlink/FileDownlink.cpp and Fw/FilePacket/StartPacket.cpp

• Added getters for variables new private variables The getters have been implemented in the header. Sometimes using references, sometimes copying values. If it is not standard, I am happy to update it.

• Fixed UT

Rationale

The a_ prefix should not be used for arguments

Testing/Review Recommendations

I am not sure if there are some breaking changes for other projects

[bocchino]

Function implementations in the header file are fine if they are short functions or they are part of a template.