Cleanup config initialization, add local config options

[droidmonkey]

• Fix Local config data is cleared when ~/.cache mounted on tempfs #5313, allow specifying local config path using environment variable and command line flag

• Add command line flag --localconfig <path> to specify a file path to use for the local configuration settings.

• Add environment variable support to set config files paths: KPXC_CONFIG and KPXC_CONFIG_LOCAL to override default locations.

• Reorder startup sequence to load specified config files earlier to allow for theme settings and other early options to be picked up.

• Removed old command line option --pw, no longer used.

• Attempt a fix of application not closing when last window is gone. Only set QApplication::setQuitOnLastWindowClosed(true) when tray icon is enabled instead of always.

Replacement for #5325

Screenshots

Testing strategy

Tested on Windows

Type of change

• ✅ Bug fix (non-breaking change that fixes an issue)
• ✅ Refactor (significant modification to existing code)

[kotoko]

When using variable KPXC_CONFIG_LOCAL should I set KPXC_CONFIG_LOCAL="~/.local/share" or KPXC_CONFIG_LOCAL="~/.local/share/keepassxc"?

[droidmonkey]

Set it to whatever you want, but this points to a file not a directory.

[kotoko]

Oh... So I guess it should be KPXC_CONFIG_LOCAL="~/.local/share/keepassxc/keepassxc.ini". Last question: will it work if keepassxc folder does not exist?

[droidmonkey]

Give it a try, test it out please

[kotoko]

OK. I tried to build keepassxc following readme (with cmake arguments -DWITH_XC_ALL=OFF -DCMAKE_BUILD_TYPE=Release) and got weird errors. For example:

/home/*****/build/CMakeFiles/CMakeTmp/src.cxx:2:44: error: too many arguments to function ‘size_t malloc_usable_size(void*)’
    2 |     int main() { malloc_usable_size(NULL, 0); return 0; }
      |                                            ^
In file included from /home/*****/build/CMakeFiles/CMakeTmp/src.cxx:1:
/usr/include/malloc.h:136:15: note: declared here
  136 | extern size_t malloc_usable_size (void *__ptr) __THROW;
      |               ^~~~~~~~~~~~~~~~~~

Given that I'm not interested in building and debugging keepassxc manually I'll just wait until this get merged to master and packaged by my linux distribution maintainers.

[phoerious]

Last question: will it work if keepassxc folder does not exist?

QSettings creates directories if they don't exist.