swarm: ctx propagation; bmt fixes; pss generic notification framework (#17150)

* cmd/swarm: minor cli flag text adjustments

* swarm/api/http: sticky footer for swarm landing page using flex

* swarm/api/http: sticky footer for error pages and fix for multiple choices

* cmd/swarm, swarm/storage, swarm: fix  mingw on windows test issues

* cmd/swarm: update description of swarm cmd

* swarm: added network ID test

* cmd/swarm: support for smoke tests on the production swarm cluster

* cmd/swarm/swarm-smoke: simplify cluster logic as per suggestion

* swarm: propagate ctx to internal apis (#754)

* swarm/metrics: collect disk measurements

* swarm/bmt: fix io.Writer interface

  * Write now tolerates arbitrary variable buffers
  * added variable buffer tests
  * Write loop and finalise optimisation
  * refactor / rename
  * add tests for empty input

* swarm/pss: (UPDATE) Generic notifications package (#744)

swarm/pss: Generic package for creating pss notification svcs

* swarm: Adding context to more functions

* swarm/api: change colour of landing page in templates

* swarm/api: change landing page to react to enter keypress

swarm/network/stream/common_test.go

@@ -250,7 +250,7 @@ func (r *TestRegistry) APIs() []rpc.API {
 }
 
 func readAll(fileStore *storage.FileStore, hash []byte) (int64, error) {
-	r, _ := fileStore.Retrieve(hash)
+	r, _ := fileStore.Retrieve(context.TODO(), hash)
 	buf := make([]byte, 1024)
 	var n int
 	var total int64