conf: more work on config changes

Add -c option to pipewire to select config file. Use this to select
the uninstalled conf file.
Rename conf properties, prefix with context.
Simplify the main daemon now that everything can go in config.
Simplify pipewire-pulse now that we can put everything in config, it's
now virtually the same as pipewire but with a differenct config file.
Parse server addresses as array of strings.

src/daemon/client-rt.conf.in

@@ -1,6 +1,6 @@
-# Daemon config file for PipeWire RT clients version @VERSION@ #
+# Real-time Client config file for PipeWire version @VERSION@ #
 
-properties = {
+context.properties = {
     ## Configure properties in the system.
     #mem.warn-mlock =		false
     #mem.allow-mlock =		true
@@ -8,7 +8,7 @@ properties = {
     #log.level =		2
 }
 
-spa-libs = {
+context.spa-libs = {
     ## <factory-name regex> = <library-name>
     #
     # Used to find spa factory names. It maps an spa factory name
@@ -19,7 +19,7 @@ spa-libs = {
     support.* =		support/libspa-support
 }
 
-modules = {
+context.modules = {
     ##  <module-name> = { [args = { <key>=<value> ... }]
     #                     [flags = [ [ifexists] [nofail] ]}
     #