Some small Labrinth refactors and fixes (#3698)

* chore(labrinth): fix typos, simplify out `remove_duplicates` func

* fix(labrinth): implement `capitalize_first` so that it can't panic on wide chars

* chore(labrinth): refactor out unneeded clone highlighted by nightly Clippy lints

* chore(labrinth): simplify `capitalize_first` implementation

* fix(labrinth): preserve ordering when deduplicating project field values

This addresses an unintended behavior change on
157647faf2778c74096e624aeef9cdb79539489c.

* fix(labrinth/tests): make `index_swaps` test run successfully

I wonder why we don't run these more often...

* refactor: rename `.env.example` files to `.env.local`, make local envs more consistent between frontend and backend

* chore(labrinth/.env.local): proper email verif. and password reset paths

apps/labrinth/.env.local

@@ -0,0 +1,123 @@
+DEBUG=true
+RUST_LOG=info,sqlx::query=warn
+SENTRY_DSN=none
+
+SITE_URL=http://localhost:3000
+CDN_URL=https://staging-cdn.modrinth.com
+LABRINTH_ADMIN_KEY=feedbeef
+RATE_LIMIT_IGNORE_KEY=feedbeef
+
+DATABASE_URL=postgresql://labrinth:labrinth@localhost/labrinth
+DATABASE_MIN_CONNECTIONS=0
+DATABASE_MAX_CONNECTIONS=16
+
+MEILISEARCH_ADDR=http://localhost:7700
+MEILISEARCH_KEY=modrinth
+
+REDIS_URL=redis://localhost
+REDIS_MAX_CONNECTIONS=10000
+
+BIND_ADDR=127.0.0.1:8000
+SELF_ADDR=http://127.0.0.1:8000
+
+MODERATION_SLACK_WEBHOOK=
+PUBLIC_DISCORD_WEBHOOK=
+CLOUDFLARE_INTEGRATION=false
+
+STORAGE_BACKEND=local
+
+MOCK_FILE_PATH=/tmp/modrinth
+
+BACKBLAZE_KEY_ID=none
+BACKBLAZE_KEY=none
+BACKBLAZE_BUCKET_ID=none
+
+S3_ACCESS_TOKEN=none
+S3_SECRET=none
+S3_URL=none
+S3_REGION=none
+S3_BUCKET_NAME=none
+
+# 1 hour
+LOCAL_INDEX_INTERVAL=3600
+# 30 minutes
+VERSION_INDEX_INTERVAL=1800
+
+RATE_LIMIT_IGNORE_IPS='["127.0.0.1"]'
+
+WHITELISTED_MODPACK_DOMAINS='["cdn.modrinth.com", "github.com", "raw.githubusercontent.com"]'
+
+ALLOWED_CALLBACK_URLS='["localhost", ".modrinth.com", "127.0.0.1"]'
+
+GITHUB_CLIENT_ID=none
+GITHUB_CLIENT_SECRET=none
+
+GITLAB_CLIENT_ID=none
+GITLAB_CLIENT_SECRET=none
+
+DISCORD_CLIENT_ID=none
+DISCORD_CLIENT_SECRET=none
+
+MICROSOFT_CLIENT_ID=none
+MICROSOFT_CLIENT_SECRET=none
+
+GOOGLE_CLIENT_ID=none
+GOOGLE_CLIENT_SECRET=none
+
+PAYPAL_API_URL=https://api-m.sandbox.paypal.com/v1/
+PAYPAL_WEBHOOK_ID=none
+PAYPAL_CLIENT_ID=none
+PAYPAL_CLIENT_SECRET=none
+PAYPAL_NVP_USERNAME=none
+PAYPAL_NVP_PASSWORD=none
+PAYPAL_NVP_SIGNATURE=none
+
+STEAM_API_KEY=none
+
+TREMENDOUS_API_URL=https://testflight.tremendous.com/api/v2/
+TREMENDOUS_API_KEY=none
+TREMENDOUS_PRIVATE_KEY=none
+TREMENDOUS_CAMPAIGN_ID=none
+
+HCAPTCHA_SECRET=none
+
+SMTP_USERNAME=none
+SMTP_PASSWORD=none
+SMTP_HOST=none
+SMTP_PORT=465
+SMTP_TLS=tls
+
+SITE_VERIFY_EMAIL_PATH=auth/verify-email
+SITE_RESET_PASSWORD_PATH=auth/reset-password
+SITE_BILLING_PATH=none
+
+SENDY_URL=none
+SENDY_LIST_ID=none
+SENDY_API_KEY=none
+
+ANALYTICS_ALLOWED_ORIGINS='["http://127.0.0.1:3000", "http://localhost:3000", "https://modrinth.com", "https://www.modrinth.com", "*"]'
+
+CLICKHOUSE_REPLICATED=false
+CLICKHOUSE_URL=http://localhost:8123
+CLICKHOUSE_USER=default
+CLICKHOUSE_PASSWORD=default
+CLICKHOUSE_DATABASE=staging_ariadne
+
+MAXMIND_LICENSE_KEY=none
+
+FLAME_ANVIL_URL=none
+
+STRIPE_API_KEY=none
+STRIPE_WEBHOOK_SECRET=none
+
+ADITUDE_API_KEY=none
+
+PYRO_API_KEY=none
+
+BREX_API_URL=https://platform.brexapis.com/v2/
+BREX_API_KEY=none
+
+DELPHI_URL=none
+DELPHI_SLACK_WEBHOOK=none
+
+ARCHON_URL=none