fix: odstranit firewall roli + pridat btop, mc, tree do base packages

Firewall (UFW) neni pozadovan:
- smazana cela role roles/firewall/
- odstraneny reference z prepare-new-server.yml
- pridana poznamka v group_vars/all.yml.example
- doporuceni: firewall resit externe (Cloudflare Tunnel, security group)

Base packages - pridany chybejici utility:
+ btop (system monitor - lepsi nez htop)
+ mc  (Midnight Commander - textovy file manager)
+ tree (struktura adresaru v terminalu)
Ponechany: curl, wget, git, vim, htop, ca-certificates, gnupg,
          lsb-release, apt-transport-https, bash-completion,
          software-properties-common, unzip, zip, rsync, net-tools

roles/common/defaults/main.yml

@@ -11,11 +11,16 @@ deploy_groups:
 
 timezone: Europe/Prague
 
-# Balíky co se instalují vždy
+# Zakladni baliky co se instaluji vzdy
 base_packages:
   - curl
   - wget
   - git
+  - unzip
+  - rsync
+  - tree
+  - btop
+  - mc
   - vim
   - htop
   - ca-certificates
@@ -24,7 +29,5 @@ base_packages:
   - apt-transport-https
   - bash-completion
   - software-properties-common
-  - unzip
   - zip
-  - rsync
   - net-tools