bgpd: Add `set as-path replace <any|ASN>` cmd for route-maps

```
route-map tstas permit 10
 set as-path replace 1
exit
```

Before:

```
donatas-laptop(config-router-af)# do show ip bgp 10.10.10.10/32
BGP routing table entry for 10.10.10.10/32, version 13
Paths: (1 available, best #1, table default)
  Advertised to non peer-group peers:
  192.168.10.65
  65000 1 2 3 123
    192.168.10.65 from 192.168.10.65 (10.10.10.11)
      Origin IGP, metric 0, valid, external, best (First path received)
      Last update: Mon Apr 25 10:39:50 2022
```

After:

```
donatas-laptop(config-router-af)# do show ip bgp 10.10.10.10/32
BGP routing table entry for 10.10.10.10/32, version 15
Paths: (1 available, best #1, table default)
  Advertised to non peer-group peers:
  192.168.10.65
  65000 65010 2 3 123
    192.168.10.65 from 192.168.10.65 (10.10.10.11)
      Origin IGP, metric 0, valid, external, best (First path received)
      Last update: Mon Apr 25 10:40:16 2022
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/yang/frr-bgp-route-map.yang b/yang/frr-bgp-route-map.yang
index 74008bc078..eaa7891f0c 100644
--- a/yang/frr-bgp-route-map.yang
+++ b/yang/frr-bgp-route-map.yang
@@ -282,6 +282,12 @@ module frr-bgp-route-map {
       "Set the BGP AS-path attribute";
   }
 
+  identity as-path-replace {
+    base frr-route-map:rmap-set-type;
+    description
+      "Replace ASNs to local AS number";
+  }
+
   identity set-community {
     base frr-route-map:rmap-set-type;
     description
@@ -793,6 +799,15 @@ module frr-bgp-route-map {
       }
     }
 
+    case as-path-replace {
+      when "derived-from-or-self(/frr-route-map:lib/frr-route-map:route-map/frr-route-map:entry/frr-route-map:set-action/frr-route-map:action, 'frr-bgp-route-map:as-path-replace')";
+      leaf replace-as-path {
+        type string;
+        description
+          "Replace ASNs to local AS number";
+      }
+    }
+
     case community {
       when "derived-from-or-self(/frr-route-map:lib/frr-route-map:route-map/frr-route-map:entry/frr-route-map:set-action/frr-route-map:action, 'frr-bgp-route-map:set-community')";
       choice community {