Initialize constructor based implementations in one place.

Change-Id: I324f25bb5ec7d792c3e015815f2a11b08f519764
Use const& arguments parameter for ctor functions.

Change-Id: I19ce8bd1a23123ac9a62a7fc95cd54fea5315221
sfx: Use constructor feature for SfxMacroLoader.

Extract that class to its own source file.

Change-Id: Idc192354b88d4489db22f6f6e9b7f5178f4030e4
sfx: Use constructor feature for SfxAppDispatchProvider.

Change-Id: I2ca8abb284e8441a49c6e96a10cf76b5680e48e2