fix: fix Linux and macOS build scripts

[WSH032]

Issues found in pytauri/example-nicegui-app#3:

• Pass the libpython path correctly on Linux and macOS as -L arguments to RUSTFLAGS.

  • In b240446 I don't know why (most likely I forgot) the -L argument was not set for linux/build.sh.
  • The -L argument in macos/build.sh is also incorrect; the quotes cause -L "\"usr\lib\"".

• Temporarily disable the appimage bundle target

  Currently unable to build appimage, see Set RPATH for pillow.libs dependencies python-pillow/Pillow#9198.

• Change the default identifier to com.username.{{ project_name }}

  Tauri no longer recommends identifiers ending with .app, see [bug] Prevent .app in identifier tauri-apps/tauri#12674.

  In fix: remove .app ending from default identifier tauri-apps/create-tauri-app#900 they changed it to com.{whoami}.{project_name}.
  I spent some time investigating and found that unless we enable the --unsafe feature to add a custom Jinja extension, we cannot obtain the username.
  So I decided to change it to com.username.{{ project_name }} for now.

[WSH032]

@ISOR3X Do you have time to review this PR?

Do you have any better suggestions for obtaining {whoami}? Or should we just use username temporarily?

[ISOR3X]

Do you have any better suggestions for obtaining {whoami}? Or should we just use username temporarily?

I think having just username is preferred over using the --unsafe flag. I guess if we ever make the pytauri-cli we can have the unsafe flag passed by default and have some python code to get the username.

[WSH032]

Thanks!

I'm increasingly feeling the limitations that scripts and copier bring to us. I agree that pytauri-cli should be put on the agenda, though I haven't had time to design it yet.