Move encrypt-all password email to EmailTemplate

[nickvergessen]

Steps

1. Install nextcloud
2. Configure an email address for the user
3. Enable encryption app occ app:enable encryption
4. Disable master key occ encryption:disable-master-key (confirm with y)
5. Enable encryption occ encryption:enable
6. Disable master key again to be sure occ encryption:disable-master-key (confirm with y)
7. Run encrypt all occ encryption:encrypt-all
   i. Do you really want to continue? (confirm with y)
   ii. Do you want to send the passwords directly to the users by mail? (confirm with y)

Before	Before	After
Regression from #10898	with fixed logo path

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[nickvergessen]

Either this PR needs to be backported or:

diff --git a/apps/encryption/templates/mail.php b/apps/encryption/templates/mail.php
index 0db4b67d08d..545d080b1d3 100644
--- a/apps/encryption/templates/mail.php
+++ b/apps/encryption/templates/mail.php
@@ -7,7 +7,7 @@
 			<table cellspacing="0" cellpadding="0" border="0" width="600px">
 				<tr>
 					<td colspan="2" bgcolor="<?php p($theme->getColorPrimary());?>">
-						<img src="<?php p(\OC::$server->getURLGenerator()->getAbsoluteURL(image_path('core', 'logo-mail.png'))); ?>" alt="<?php p($theme->getName()); ?>"/>
+						<img src="<?php p(\OC::$server->getURLGenerator()->getAbsoluteURL(image_path('core', 'logo/logo-mail.png'))); ?>" alt="<?php p($theme->getName()); ?>"/>
 					</td>
 				</tr>
 				<tr><td colspan="2">&nbsp;</td></tr>

To prevent the exception from the first "Before" screenshot.

I would vote for backporting this PR here to 26 after 26.0.0 is out (string freeze) and backporting the above diff to all other versions.

[nickvergessen]

/backport to stable26

[kesselb]

Cool 😎

[joshtrichards]

Also fixes #35808 (but not for NC25 as-is until #36351 (comment) gets created in a separate PR).

[nickvergessen]

Feel free to send it as a Pull Request