sign: API changes for public keys and CLI keys format

API changes:
- added function `ostree_sign_add_pk()` for multiple public keys using.
- `ostree_sign_set_pk()` now substitutes all previously added keys.
- added function `ostree_sign_load_pk()` allowed to load keys from file.
- `ostree_sign_ed25519_load_pk()` able to load the raw keys list from file.
- use base64 encoded public and private ed25519 keys for CLI and keys file.

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

src/libostree/ostree-sign-ed25519.h

@@ -63,7 +63,13 @@ gboolean ostree_sign_ed25519_set_pk (OstreeSign *self,
                                      GVariant *public_key,
                                      GError **error);
 
-void ostree_sign_ed25519_finalize (GObject *gobject);
+gboolean ostree_sign_ed25519_add_pk (OstreeSign *self,
+                                     GVariant *public_key,
+                                     GError **error);
+
+gboolean ostree_sign_ed25519_load_pk (OstreeSign *self,
+                                      GVariant *options,
+                                      GError **error);
 
 _OSTREE_PUBLIC
 gboolean ostree_sign_ed25519_keypair_generate (OstreeSign *self,
@@ -71,5 +77,6 @@ gboolean ostree_sign_ed25519_keypair_generate (OstreeSign *self,
                                                GVariant **out_public_key,
                                                GError **error);
 
+
 G_END_DECLS