fix: components dir content is duplicated for sddm

Preserve symlink on install.

As discussed with @davidedmundson:

I see something wrong here:

$ find usr/ -iname "*keyboardl*qml" 
usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/KeyboardLayoutButton.qml
usr/share/sddm/themes/breeze/components/KeyboardLayoutButton.qml

the files are the same, and they are not a symlink..

Here what we have in the source dir:

⬢[bam@toolbox plasma-workspace]$ ll ~/kde/src/plasma-workspace/sddm-theme/
total 780
-rw-rw-r--. 1 bam bam   2078 Apr 26  2020 Background.qml
-rw-rw-r--. 1 bam bam    814 Apr 26  2020 BreezeMenuStyle.qml
-rw-r--r--. 1 bam bam   1164 Oct  3 00:32 KeyboardButton.qml
-rw-r--r--. 1 bam bam   4134 Oct  3 00:32 Login.qml
-rw-r--r--. 1 bam bam  20302 Oct  3 00:32 Main.qml
-rw-r--r--. 1 bam bam   1851 Oct  3 00:32 SessionButton.qml
lrwxrwxrwx. 1 bam bam     35 Apr 26  2020 components -> ../lookandfeel/contents/components/
-rw-rw-r--. 1 bam bam   5681 Apr 26  2020 default-logo.svg
drwxrwxr-x. 1 bam bam    148 Apr 26  2020 dummydata
drwxrwxr-x. 1 bam bam     20 Apr 26  2020 faces
-rw-r--r--. 1 bam bam   2123 Oct  3 00:32 metadata.desktop
-rw-r--r--. 1 bam bam 729372 Oct  3 00:32 preview.png
-rw-rw-r--. 1 bam bam    236 Apr 26  2020 theme.conf.cmake

And here is the link created on install:

⬢[bam@toolbox plasma-workspace]$ ll  ~/kde/usr/share/sddm/themes/breeze/components
lrwxrwxrwx. 1 bam bam 72 Oct 25 23:52 /home/bam/kde/usr/share/sddm/themes/breeze/components -> ../../../plasma/look-and-feel/org.kde.breeze.desktop/contents/components

instead of duplicating the whole dereferenced dir.