Long render time if an attribute template is selected in the BE list

[zonky2]

Long render time if an attribute template is selected in the BE list e.g. mm_attr_text.html5 with simple <h3>-Tag

Test (only response time):

• list with 10 items and without sub-template: 416ms
• 10 items and one attribute with own template: 626ms
• 10 items and two attribute with own template: 895ms
• 20 items and two attribute with own template: 1.641ms
• 160 items and two attribute with own template: 8.428ms
• 160 items without own attribute template: 722ms

[zonky2]

check this issue with @discordier:

we should add cache for non-existent files at Template.php https://github.com/MetaModels/core/blob/33244d82cce0469c7b4040355ba22f9fdf7001b4/src/Render/Template.php#L250

Workaround: add to your .html5 template the same as .text

[zonky2]

duplicate of https://github.com/MetaModels/core/issues/1149