repart: add GrowFileSystem= setting to set new GPT partition flag for newly created partitions

And set it to on by default, except if partition is marked read-only.

src/shared/gpt.c

@@ -163,3 +163,14 @@ bool gpt_partition_type_knows_read_only(sd_id128_t id) {
                 gpt_partition_type_is_root_verity(id) || /* pretty much implied, but let's set the bit to make things really clear */
                 gpt_partition_type_is_usr_verity(id);    /* ditto */
 }
+
+bool gpt_partition_type_knows_growfs(sd_id128_t id) {
+        return gpt_partition_type_is_root(id) ||
+                gpt_partition_type_is_usr(id) ||
+                sd_id128_in_set(id,
+                                GPT_HOME,
+                                GPT_SRV,
+                                GPT_VAR,
+                                GPT_TMP,
+                                GPT_XBOOTLDR);
+}

src/shared/gpt.h

@@ -136,3 +136,4 @@ bool gpt_partition_type_is_usr(sd_id128_t id);
 bool gpt_partition_type_is_usr_verity(sd_id128_t id);
 
 bool gpt_partition_type_knows_read_only(sd_id128_t id);
+bool gpt_partition_type_knows_growfs(sd_id128_t id);