Various changes to improve compilation of RT on macOS thanks to @Benitoite and @Pandagrapher
* mac: use sed -i.bak, add X's to mktemp template in macosx_bundle.sh
* mac: test lensfun version in macosx_bundle.sh to select correct lensfun database version (version_1 for 3.2 and version_2 for 3.95)
* mac: remove DYLD_FALLBACK_LIBRARY_PATH from main Info.plist
* mac: removes some -cli codesigning commands
* mac: remove erroneous newlines in macosx_bundle.sh and suppress superfluous codesigning of Contents/Frameworks/*dylib
* mac: Apple arm64/homebrew compatibility update
* mac: CMakeLists.txt arm64 homebrew compatibility
* mac: add Apple arm64 CPU native flag
* mac: fix pixbuf query syntax
* mac: adapt. of Pandagrapher's patch
* mac: additional instructions for the -cli exec.
* mac: revert target 10
* mac: remove legacy environment variable Per https://github.com/Beep6581/RawTherapee/pull/5786#issuecomment-792276656
* mac: fix destination of credits/license
* mac: copy {LOCAL_PREFIX}/share/locale to bundle
* mac: fixes a path for the License
* mac: fix of UpdateInfo command structure
* mac: remove redundant copying
* mac: use cmake to configure Info.plist values
* mac: configurator for Info.plist version values
* mac: fix locale detection / language
* mac: remove an outdated key from Info.plist
* mac: fix path usage for gtk.immodules / locale dir
* mac: revert a change merged elsewhere
* mac: follow more symlinks for 'brew builds
* mac: link to CoreFoundation for locale detection
* mac: link CoreFoundation for locale / C
* mac: detect locale with CoreFoundation per https://github.com/Beep6581/RawTherapee/pull/5786#issuecomment-798926898
* mac: remove outdated lines
* Update multilangmgr.cc
* mac: Info.plist language fixes (Pandagrapher) https://github.com/Beep6581/RawTherapee/pull/5786#issuecomment-813004475
* Mac: also package libpng12 for homebrew compatibility.
* macOS packaging and language updates
