[GITEA] Optionally allow anyone to edit Wikis

This is largely based on gitea#6312 by @ashimokawa, with updates and
fixes by myself, and incorporates the review feedback given in that pull
request, and more.

What this patch does is add a new "default_permissions" column to the
`repo_units` table (defaulting to read permission), adjusts the
permission checking code to take this into consideration, and then
exposes a setting that lets a repo administrator enable any user on a
Forgejo instance to edit the repo's wiki (effectively giving the wiki
unit of the repo "write" permissions by default).

By default, wikis will remain restricted to collaborators, but with the
new setting exposed, they can be turned into globally editable wikis.

Fixes Codeberg/Community#28.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
(cherry picked from commit 4b74439922)
(cherry picked from commit 337cf62c10)
(cherry picked from commit b6786fdb32)
(cherry picked from commit a5d2829a10)

[GITEA] Optionally allow anyone to edit Wikis (squash) AddTokenAuth

(cherry picked from commit fed50cf72e)
(cherry picked from commit 42c55e494e)
(cherry picked from commit e3463bda47)

models/repo/repo_unit.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/perm"
 	"code.gitea.io/gitea/models/unit"
 	"code.gitea.io/gitea/modules/json"
 	"code.gitea.io/gitea/modules/setting"
@@ -39,13 +40,43 @@ func (err ErrUnitTypeNotExist) Unwrap() error {
 	return util.ErrNotExist
 }
 
+// RepoUnitAccessMode specifies the users access mode to a repo unit
+type UnitAccessMode int
+
+const (
+	// UnitAccessModeUnset - no unit mode set
+	UnitAccessModeUnset UnitAccessMode = iota // 0
+	// UnitAccessModeNone no access
+	UnitAccessModeNone // 1
+	// UnitAccessModeRead read access
+	UnitAccessModeRead // 2
+	// UnitAccessModeWrite write access
+	UnitAccessModeWrite // 3
+)
+
+func (mode UnitAccessMode) ToAccessMode(modeIfUnset perm.AccessMode) perm.AccessMode {
+	switch mode {
+	case UnitAccessModeUnset:
+		return modeIfUnset
+	case UnitAccessModeNone:
+		return perm.AccessModeNone
+	case UnitAccessModeRead:
+		return perm.AccessModeRead
+	case UnitAccessModeWrite:
+		return perm.AccessModeWrite
+	default:
+		return perm.AccessModeNone
+	}
+}
+
 // RepoUnit describes all units of a repository
 type RepoUnit struct { //revive:disable-line:exported
-	ID          int64
-	RepoID      int64              `xorm:"INDEX(s)"`
-	Type        unit.Type          `xorm:"INDEX(s)"`
-	Config      convert.Conversion `xorm:"TEXT"`
-	CreatedUnix timeutil.TimeStamp `xorm:"INDEX CREATED"`
+	ID                 int64
+	RepoID             int64              `xorm:"INDEX(s)"`
+	Type               unit.Type          `xorm:"INDEX(s)"`
+	Config             convert.Conversion `xorm:"TEXT"`
+	CreatedUnix        timeutil.TimeStamp `xorm:"INDEX CREATED"`
+	DefaultPermissions UnitAccessMode     `xorm:"NOT NULL DEFAULT 0"`
 }
 
 func init() {