Implement notification subcommands (#389)

- [x] enhance notification listing
  - add `--states` and `--type` filters
  - toggle per-user or per-repo listing via `--mine` flag
  - print more fields
- [x] add subcommands to mark notifications as read, unread, pinned, unpinned. operates on
  - all notifications matching the `--state` and `--mine` filter flags, or
  - a notification specified by ID.
- [ ] ~~add a `--fields` flag for notifications listing.~~ *not in this PR*
- [ ] ~~interactive mode~~ *not in this PR*. this would go well together with #324

fixes #243, fixes #155

based on initial work in #283 and #386, but opening a new PR for @6543 to review as I changed quite a lot

---

### ⚠️ breaking ⚠️
- `tea notifications --all` has moved to `tea notifications --mine`
- `tea notifications` now only works with the context of a remote repo.
  To run this outside of a local git dir, run either `tea n --mine` or `tea n --repo <my/repo>`

---

Co-authored-by: Karl Heinz Marbaise <kama@soebes.de>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Norwin Roosen <git@nroo.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/389
Reviewed-by: 6543 <6543@obermui.de>
Reviewed-by: Alexey 〒erentyev <axifive@noreply.gitea.io>
Co-authored-by: Norwin <noerw@noreply.gitea.io>
Co-committed-by: Norwin <noerw@noreply.gitea.io>

cmd/times/list.go

@@ -19,6 +19,17 @@ import (
 	"github.com/urfave/cli/v2"
 )
 
+// NOTE: not using NewCsvFlag, as we don't want an alias & default value.
+var timeFieldsFlag = &flags.CsvFlag{
+	AvailableFields: print.TrackedTimeFields,
+	StringFlag: cli.StringFlag{
+		Name: "fields",
+		Usage: fmt.Sprintf(`Comma-separated list of fields to print. Available values:
+	%s
+`, strings.Join(print.TrackedTimeFields, ",")),
+	},
+}
+
 // CmdTrackedTimesList represents a sub command of times to list them
 var CmdTrackedTimesList = cli.Command{
 	Name:    "list",
@@ -53,12 +64,7 @@ Depending on your permissions on the repository, only your own tracked times mig
 			Aliases: []string{"m"},
 			Usage:   "Show all times tracked by you across all repositories (overrides command arguments)",
 		},
-		&cli.StringFlag{
-			Name: "fields",
-			Usage: fmt.Sprintf(`Comma-separated list of fields to print. Available values:
-			%s
-		`, strings.Join(print.TrackedTimeFields, ",")),
-		},
+		timeFieldsFlag,
 	}, flags.AllDefaultFlags...),
 }
 
@@ -116,7 +122,7 @@ func RunTimesList(cmd *cli.Context) error {
 	}
 
 	if ctx.IsSet("fields") {
-		if fields, err = flags.GetFields(cmd, print.TrackedTimeFields); err != nil {
+		if fields, err = timeFieldsFlag.GetValues(cmd); err != nil {
 			return err
 		}
 	}