feat(logs): 'uc machine logs' to view logs from systemd services on machines (#283)

* logging: client side

Create internal/logs and put abstracted way service and machine logging in there
This adds the bits to do machine logging of the services.

See #273 and discussion in #158

Signed-off-by: Miek Gieben <miek@miek.nl>

* go mod tidy

Signed-off-by: Miek Gieben <miek@miek.nl>

* fix typo

Signed-off-by: Miek Gieben <miek@miek.nl>

* Hook it up further

Signed-off-by: Miek Gieben <miek@miek.nl>

* Check unit validity server side

Signed-off-by: Miek Gieben <miek@miek.nl>

* Make cli-docs

Signed-off-by: Miek Gieben <miek@miek.nl>

* Add newline to logs

Signed-off-by: Miek Gieben <miek@miek.nl>

* docs

Signed-off-by: Miek Gieben <miek@miek.nl>

* Polish a bit

Signed-off-by: Miek Gieben <miek@miek.nl>

* comment fix

Signed-off-by: Miek Gieben <miek@miek.nl>

* There is no groupid

Signed-off-by: Miek Gieben <miek@miek.nl>

---------

Signed-off-by: Miek Gieben <miek@miek.nl>

go.mod

@@ -38,6 +38,7 @@ require (
 	github.com/psviderski/unregistry v0.4.1
 	github.com/siderolabs/grpc-proxy v0.5.1
 	github.com/spf13/cobra v1.10.1
+	github.com/spf13/pflag v1.0.10
 	github.com/stretchr/testify v1.11.1
 	github.com/vishvananda/netlink v1.3.1
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba
@@ -273,7 +274,6 @@ require (
 	github.com/smallstep/scep v0.0.0-20231024192529-aee96d7ad34d // indirect
 	github.com/smallstep/truststore v0.13.0 // indirect
 	github.com/spf13/cast v1.7.0 // indirect
-	github.com/spf13/pflag v1.0.10 // indirect
 	github.com/stoewer/go-strcase v1.2.0 // indirect
 	github.com/stretchr/objx v0.5.2 // indirect
 	github.com/tailscale/tscert v0.0.0-20240517230440-bbccfbf48933 // indirect