/hierarchy - return public and knockable rooms for authed users

When requesting the room hierarchy with an authenticated user, return public and knockable rooms.

According to the spec, https://github.com/matrix-org/matrix-spec-proposals/blob/main/proposals/2946-spaces-summary.md

```
Any child room that the user is joined or is potentially joinable is included in the response.
```

This is currently not the case. See discussion here: https://matrix.to/#/!NasysSDfxKxZBzJJoE:matrix.org/$t2Csj-6y1PVsn8GOnFZfXzeQW13NfqvrFCxB-XI_uhA?via=matrix.org&via=libera.chat&via=element.io and here: https://matrix.to/#/!NasysSDfxKxZBzJJoE:matrix.org/$EHp1x1DY7tnYZtx_PVEb-sKB9lmJajqHx2uGlhrRh6k?via=matrix.org&via=libera.chat&via=element.io

Test Plan:
create and register clients bob and alice
have bob create a public space
have bob create a public room parented to the space
have alice join the space(room)
have alice sync the space
expect alice to see two rooms in the space hierarchy, the space and the child room

.github/workflows/dendrite.yml

@@ -132,11 +132,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-<<<<<<< HEAD
         go: ["1.18", "1.19"]
-=======
-        go: ["1.18"]
->>>>>>> 698369f5 (merge latest changes from dendrite main (#15))
         goos: ["linux"]
         goarch: ["amd64", "386"]
     steps:
@@ -170,11 +166,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-<<<<<<< HEAD
         go: ["1.18", "1.19"]
-=======
-        go: ["1.18"]
->>>>>>> 698369f5 (merge latest changes from dendrite main (#15))
         goos: ["windows"]
         goarch: ["amd64"]
     steps:

setup/mscs/msc2946/msc2946.go

@@ -45,6 +45,9 @@ const (
 	ConstCreateEventContentValueSpace = "m.space"
 	ConstSpaceChildEventType          = "m.space.child"
 	ConstSpaceParentEventType         = "m.space.parent"
+	ConstJoinRulePublic               = "public"
+	ConstJoinRuleKnock                = "knock"
+	ConstJoinRuleRestricted           = "restricted"
 )
 
 type MSC2946ClientResponse struct {