Switch library and tests to the x509_oid module

```
git grep -l -P 'mbedtls_oid_get_(?!numeric_string\b)' | xargs perl -i -pe 's/\bmbedtls_oid_get_(?!numeric_string\b)/mbedtls_x509_oid_get_/'
./framework/scripts/code_style.py --since HEAD~1 --fix
```

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 959ae21..5528763 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -926,7 +926,7 @@
         /*
          * Detect supported extensions
          */
-        ret = mbedtls_oid_get_x509_ext_type(&extn_oid, &ext_type);
+        ret = mbedtls_x509_oid_get_x509_ext_type(&extn_oid, &ext_type);
 
         if (ret != 0) {
             /* Give the callback (if any) a chance to handle the extension */
@@ -1692,7 +1692,7 @@
     const char *sep = "";
 
     while (cur != NULL) {
-        if (mbedtls_oid_get_extended_key_usage(&cur->buf, &desc) != 0) {
+        if (mbedtls_x509_oid_get_extended_key_usage(&cur->buf, &desc) != 0) {
             desc = "???";
         }
 
@@ -1721,7 +1721,7 @@
     const char *sep = "";
 
     while (cur != NULL) {
-        if (mbedtls_oid_get_certificate_policies(&cur->buf, &desc) != 0) {
+        if (mbedtls_x509_oid_get_certificate_policies(&cur->buf, &desc) != 0) {
             desc = "???";
         }