Mention alternative app stores on website and in Github repository

### Problem Description

Currently this app is in Huawei appgallery and Samsung Galaxy store, but it's not mentioned anywhere. And also
F-Droid avaiablity isn't metioned on a website.

### Proposed Solution

Add Huawei appgallery and Samsung Galaxy store links to Github repository. On website create alternative app stores section similar to the one on Adguard for Android and Adguard VPN websites. with F-Droid, Huawei appgallery and Samsung Galaxy store links.
### Alternatives Considered

Search for app in this app stores or download it from Play Store, F-Droid or Github relases.

### Additional Information

Part of Github repository README to add it:
https://github.com/AdguardTeam/ContentBlocker?tab=readme-ov-file#releases

Links to Huawei appgallery and Samsung Galaxy store:
https://appgallery.huawei.com/app/C100440597
https://galaxystore.samsung.com/detail/com.adguard.android.contentblocker

Review the GitHub repository README at the Releases section and compare the website with the referenced AdGuard for Android and AdGuard VPN alternative app-store sections. Add links for F-Droid, Huawei AppGallery, and Samsung Galaxy Store in both places, with the website presenting an equivalent alternative app stores section. Done when all listed stores are linked and discoverable in the README and website.

索引モデルが issue の本文から書いたものです。