yadm: add pages (#13920)

Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>
Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>

pages/common/yadm-init.md

@@ -0,0 +1,17 @@
+# yadm-init
+
+> Initialize a new, empty repository for tracking dotfiles.
+> The repository is stored in `$HOME/.local/share/yadm/repo.git`.
+> More information: <https://yadm.io/docs/getting_started>.
+
+- Execute:
+
+`yadm init`
+
+- Override the worktree:
+
+`yadm init -w {{path/to/worktree_folder}}`
+
+- Overwrite an existing repository:
+
+`yadm init -f {{path/to/local_repository}}`