Add OJS 3.5 support and a configurable article count

[edersotto]

What this adds

This PR brings the Most Read block plugin to OJS 3.5, plus a small feature.

1. OJS 3.5 compatibility

• Replace PKP\cache\CacheManager with the Illuminate\Support\Facades\Cache facade.
• Replace APP\i18n\AppLocale / APP\core\Services usage with the PKP\facades\Locale
  facade and Repo.
• Adjust namespaced imports accordingly.

These calls target 3.5 APIs, so the branch is meant for the 3.5.x line (it will not run
on 3.4). See the note on branching below.

2. Configurable number of articles

A new "Number of articles" (mostReadCount) setting lets journal managers choose how
many items the block shows, with validation (whole number ≥ 1). Existing behavior is
preserved when the field is left empty.

3. Template hardening

• Escape output (|escape) and only render the block when there are results
  ({if !empty($mostRead)}).
• Rename the block CSS class from block_developed_by to block_most_read.

4. Housekeeping

• PSR-12 formatting on the two PHP classes.
• New locale keys (settings.count, settings.mostReadCountInvalid,
  settings.mostReadDaysRequired) added to en and pt_BR.
• version.xml bumped to 3.5.0.1 (copyright header unchanged).

A note on branching

The changes require 3.5 and would break 3.4 if merged straight into a 3.4 master.
If you'd prefer, I'm happy to retarget this to a stable-3_5_0 branch (or rebase it
however you cut new OJS lines) — just let me know.

Context / credit

These changes come from work done at OJSBR while adapting the
plugin for OJS 3.5 deployments. Thanks for maintaining Most Read — it's widely used in the
Brazilian OJS community. Happy to iterate on anything here.

[ajnyga]

thanks for this, looked very good with a quick glance.

I am on vacation right now, but will merge this soon.

I will move 3.4 to a dedicated branch and merge this to master to match the current main release of OJS. This is how I usually do with other plugins as well.