PPCSymbolDB: Refactor SymbolMap Save/Load

[sepalani]

This PR refactors parts of the loading/saving process of symbol map. I'm putting it as a draft for now as I'd like to wait for https://dolp.in/pr13113 to be merged first.

This PR fixes issues I had where some symbols weren't loaded properly (which might get saved later). Here are some examples on how they can alter existing symbol maps.

The alignment wasn't properly detected and 0 was detected as name by sscanf.

This issue was also caused by the namepos/strstr logic which is flawed when the name is small and equals to part of the symbol address, size of vaddress. Moreover, checking for a space doesn't work when alignment is 16. I've seen this alignment value on some *fill* symbols.

-80468370 00000008 80468370 0 TRKPositionFile (entry of .text)  TRK_Hollywood_Revolution.a C:\products\RVL\runtime_libs\debugger\embedded\MetroTRK\Processor\
+80468360 00000008 80468360 0 0468360 00000008 80468360 0 TRKPositionFile (entry of .text)      TRK_Hollywood_Revolution.a C:\products\RVL\runtime_libs\debugger\embedded\MetroTRK\Processor\

savegpr / loadgpr entry wasn't properly detected

This issue also trimmed the object names after the "entry of" part.

-80456e54 000018 80456e54 0 _restgpr_27 (entry of __restore_gpr)        Runtime.PPCEABI.H.a runtime.o
+80456e54 000018 80456e54 0 __restore_gpr::

This PR is ready to be reviewed and tested. I also advise people testing PR to backup their symbol maps just in case or test this PR in a dedicated portable build.