Preview images for Issue cards in Project Board view (#22112)

Original Issue: https://github.com/go-gitea/gitea/issues/22102

This addition would be a big benefit for design and art teams using the
issue tracking.

The preview will be the latest "image type" attachments on an issue-
simple, and allows for automatic updates of the cover image as issue
progress is made!

This would make Gitea competitive with Trello... wouldn't it be amazing
to say goodbye to Atlassian products? Ha.

First image is the most recent, the SQL will fetch up to 5 latest images
(URL string).

All images supported by browsers plus upcoming formats: *.avif *.bmp
*.gif *.jpg *.jpeg *.jxl *.png *.svg *.webp

The CSS will try to center-align images until it cannot, then it will
left align with overflow hidden. Single images get to be slightly
larger!

Tested so far on: Chrome, Firefox, Android Chrome, Android Firefox.

Current revision with light and dark themes:

![image](https://user-images.githubusercontent.com/24665/207066878-58e6bf73-0c93-4caa-8d40-38f4432b3578.png)


![image](https://user-images.githubusercontent.com/24665/207066555-293f65c3-e706-4888-8516-de8ec632d638.png)

---------

Co-authored-by: Jason Song <i@wolfogre.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

models/project/project.go

@@ -19,12 +19,18 @@ import (
 )
 
 type (
-	// ProjectsConfig is used to identify the type of board that is being created
-	ProjectsConfig struct {
+	// BoardConfig is used to identify the type of board that is being created
+	BoardConfig struct {
 		BoardType   BoardType
 		Translation string
 	}
 
+	// CardConfig is used to identify the type of board card that is being used
+	CardConfig struct {
+		CardType    CardType
+		Translation string
+	}
+
 	// Type is used to identify the type of project in question and ownership
 	Type uint8
 )
@@ -91,6 +97,7 @@ type Project struct {
 	CreatorID   int64                  `xorm:"NOT NULL"`
 	IsClosed    bool                   `xorm:"INDEX"`
 	BoardType   BoardType
+	CardType    CardType
 	Type        Type
 
 	RenderedContent string `xorm:"-"`
@@ -145,15 +152,23 @@ func init() {
 	db.RegisterModel(new(Project))
 }
 
-// GetProjectsConfig retrieves the types of configurations projects could have
-func GetProjectsConfig() []ProjectsConfig {
-	return []ProjectsConfig{
+// GetBoardConfig retrieves the types of configurations project boards could have
+func GetBoardConfig() []BoardConfig {
+	return []BoardConfig{
 		{BoardTypeNone, "repo.projects.type.none"},
 		{BoardTypeBasicKanban, "repo.projects.type.basic_kanban"},
 		{BoardTypeBugTriage, "repo.projects.type.bug_triage"},
 	}
 }
 
+// GetCardConfig retrieves the types of configurations project board cards could have
+func GetCardConfig() []CardConfig {
+	return []CardConfig{
+		{CardTypeTextOnly, "repo.projects.card_type.text_only"},
+		{CardTypeImagesAndText, "repo.projects.card_type.images_and_text"},
+	}
+}
+
 // IsTypeValid checks if a project type is valid
 func IsTypeValid(p Type) bool {
 	switch p {
@@ -237,6 +252,10 @@ func NewProject(p *Project) error {
 		p.BoardType = BoardTypeNone
 	}
 
+	if !IsCardTypeValid(p.CardType) {
+		p.CardType = CardTypeTextOnly
+	}
+
 	if !IsTypeValid(p.Type) {
 		return util.NewInvalidArgumentErrorf("project type is not valid")
 	}
@@ -280,9 +299,14 @@ func GetProjectByID(ctx context.Context, id int64) (*Project, error) {
 
 // UpdateProject updates project properties
 func UpdateProject(ctx context.Context, p *Project) error {
+	if !IsCardTypeValid(p.CardType) {
+		p.CardType = CardTypeTextOnly
+	}
+
 	_, err := db.GetEngine(ctx).ID(p.ID).Cols(
 		"title",
 		"description",
+		"card_type",
 	).Update(p)
 	return err
 }