Cleanup: stale profile reference, unhidden uninstall profile, .po header, ChangeLog URL

A bundle of minor, low-risk cleanups found during the 2.0.0 release-readiness review (see #144). Could be addressed as one small PR.

1. **Stale HiddenProfiles entry** — `src/pas/plugins/ldap/plonecontrolpanel/__init__.py` lists `pas.plugins.ldap.plonecontrolpanel:install-base`, but no `install-base` profile exists (only `default` and `uninstall`). Hiding a non-existent profile is a no-op but misleading.

2. **Uninstall profile not hidden** — the `pas.plugins.ldap.plonecontrolpanel:uninstall` profile is currently *not* in `HiddenProfiles`, so it shows up in the add-ons "uninstall profiles" list. Consider hiding it.

3. **English `.po` Domain header** — `src/pas/plugins/ldap/locales/en/LC_MESSAGES/pas.plugins.ldap.po` header still reads `Domain: DOMAIN`; the `es` catalog correctly has `Domain: pas.plugins.ldap`.

4. **ChangeLog URL points to `master`** — `pyproject.toml` `[project.urls]` ChangeLog uses `/blob/master/CHANGES.rst`, but the default branch is `main`.

All cosmetic / non-functional.

Review the profile declarations in src/pas/plugins/ldap/plonecontrolpanel/__init__.py, the headers in src/pas/plugins/ldap/locales/en/LC_MESSAGES/pas.plugins.ldap.po and the matching es catalog, and the [project.urls] section of pyproject.toml. Confirm the available profiles and branch name first; done means the stale profile reference is removed, uninstall is hidden, the English Domain matches the Spanish catalog, and the ChangeLog URL uses main.

Written by the indexing model from the issue text.