feat(repl): Add import-vcard and make-vcard commands (#7048)

- Added import-vcard and make-vcard commands to deltachat-repl. These
  wrap the corresponding import_vcard() and make_vcard() operations from
  src/contact.rs. Each command takes a file path argument specifying the
  location of the vCard file to be read or written. The make-vcard command
  takes one or more IDs to write to the file.
- Documented commands in "Using the CLI client" section of README.md.

Co-authored-by: iequidoo <117991069+iequidoo@users.noreply.github.com>

deltachat-repl/src/main.rs

@@ -232,7 +232,7 @@ const MESSAGE_COMMANDS: [&str; 10] = [
     "delmsg",
     "react",
 ];
-const CONTACT_COMMANDS: [&str; 7] = [
+const CONTACT_COMMANDS: [&str; 9] = [
     "listcontacts",
     "addcontact",
     "contactinfo",
@@ -240,6 +240,8 @@ const CONTACT_COMMANDS: [&str; 7] = [
     "block",
     "unblock",
     "listblocked",
+    "import-vcard",
+    "make-vcard",
 ];
 const MISC_COMMANDS: [&str; 14] = [
     "getqr",