[feature] Set default header and avatar for API accounts to GtS ones (#799)

* validate web-asset-base-dir

* move default icons into converter

* always ensure avatar + header on api accounts

* update tests

* add default header

* don't return error from web module creation anymore

* tidy a bit

* use pngs for default avatars rather than svgs

internal/web/thread.go

@@ -23,7 +23,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"math/rand"
 	"net/http"
 	"strings"
 
@@ -36,21 +35,6 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
 )
 
-var randAvatars = make(map[string]string)
-
-func (m *Module) ensureAvatar(status apimodel.Status) {
-	if status.Account.Avatar == "" && len(m.defaultAvatars) > 0 {
-		avatar, ok := randAvatars[status.Account.ID]
-		if !ok {
-			//nolint:gosec
-			randomIndex := rand.Intn(len(m.defaultAvatars))
-			avatar = m.defaultAvatars[randomIndex]
-			randAvatars[status.Account.ID] = avatar
-		}
-		status.Account.Avatar = avatar
-	}
-}
-
 func (m *Module) threadGETHandler(c *gin.Context) {
 	ctx := c.Request.Context()
 
@@ -120,16 +104,6 @@ func (m *Module) threadGETHandler(c *gin.Context) {
 		return
 	}
 
-	m.ensureAvatar(*status)
-
-	for _, status := range context.Descendants {
-		m.ensureAvatar(status)
-	}
-
-	for _, status := range context.Ancestors {
-		m.ensureAvatar(status)
-	}
-
 	c.HTML(http.StatusOK, "thread.tmpl", gin.H{
 		"instance": instance,
 		"status":   status,