Add support to Xcode 16 folders

[alexandre-pod]

This PR adds support to new synchronised folders introduced by Xcode 16, and also adds support for SPM projects.

Added

• Add support for Swift Packages and Xcode 16 synchronized folders
  • Add new optional variable nammed "project_type" which accepts 2 values: "xcode" and "filesystem". When missing ccios use "xcode" by default.
  • When "project_type" is set to "filesystem" ccios will not try to update a pbxproj and will only generate files.
  • When "project_type" is set to "filesystem" multi target definition is no longer supported for generated files.
  • When generating files for an filesystem project, the target name in the header is either: the target defined in the template variables, the target defined in .ccios.yml, or it will try to guess the name when using SPM by searching the target name inside the standard naming scheme of: "Sources/<target_name>/".

Limitations with project_type: "xcode" and Xcode 16 synchronised folders:

• Targets configuration (with a template or a configuration) are no longer supported for files generated inside a synchronised folder, it will simply use the targets in which this folder is. A warning is printed on the console when a target in which the file should have been does not contain this folder.
• This is currently not working until those 2 PR are merged, this is because the generated pbxproj has some format differences that cause unwanted changes:
  • Fix exception set comment to match Xcode CocoaPods/Xcodeproj#1000 (for the wrong comment in a section)
  • Format synchronized root groups as flat dictionary CocoaPods/Nanaimo#67 (for the xml formatting on some section)

[ThibaultFarnier]

Ça m'a l'air ok dans les grandes lignes, la présence de tests me rassure pas mal, ne comprenant pas forcément toutes les subtilités de la Gem. Merci beaucoup en tout cas 🙏