docs: update documentation (#25440)

* docs: beginning of the year tune up and updates

* darker dark

* backup information

* promote to table of content

* Apply suggestions from code review

Co-authored-by: Mert <101130780+mertalev@users.noreply.github.com>
Co-authored-by: Mees Frensel <33722705+meesfrensel@users.noreply.github.com>

* restore and backup

* edit

* Apply suggestions from code review

Co-authored-by: bo0tzz <git@bo0tzz.me>

* feedback

* more information on mobile

Co-authored-by: https://github.com/aviv926

* more information on free up space
>
> Co-authored-by: jtagcat <git-12dbd862@jtag.cat>

* Update docs/docs/features/mobile-app.mdx

Co-authored-by: jtagcat <git-12dbd862@jtag.cat>

* screenshot and minor tweaks

---------

Co-authored-by: Mert <101130780+mertalev@users.noreply.github.com>
Co-authored-by: Mees Frensel <33722705+meesfrensel@users.noreply.github.com>
Co-authored-by: bo0tzz <git@bo0tzz.me>
Co-authored-by: jtagcat <git-12dbd862@jtag.cat>

docs/docusaurus.config.js

@@ -76,6 +76,10 @@ const config = {
           autoCollapseCategories: false,
         },
       },
+      tableOfContents: {
+        minHeadingLevel: 2,
+        maxHeadingLevel: 4,
+      },
       navbar: {
         logo: {
           alt: 'Immich Logo',