Big namespace cleanup

[firebird-automations]

Put all namespaces inside the Firebird namespace.

Avoid qualification of namespace when inside it or in children namespaces.

Put *_proto.h headers in namespaces.

[aafemt]

Move Why namespace inside Firebird
Move Replication namespace to Firebird::Jrd::Replication
Move namespace Ods to Firebird::Jrd::Ods

What's the purpose? It makes even less sense in company with "using namespace Firebird" everywhere.

It looks like you just wanna to kill every open PR with endless merge conflicts and build errors.