Add docker build support and deployment

[nae-stormrage]

Description

Adds Docker support for building and running ArgusCore.

Single multi-stage Dockerfile with dedicated targets:

• build — compiles worldserver and bnetserver from source (Ubuntu 24.04, CMake + Ninja + Boost)
• tdb-download — downloads and extracts the TDB release (world + hotfixes SQL) from GitHub, independent of the build stage
• runtime-base - shared lightweight runtime layer with compiled binaries;
• worldserver/bnetserver - final runtime images, built FROM runtime-base;
• db-init - separate Ubuntu-based image that sequentially applies the SQL files needed to bootstrap the databases (create_mysql.sql, auth_database.sql, characters_database.sql, TDB_*_7.3.5.26972.sql).

docker-compose.yml orchestrating mysql, db-init, bnetserver, and worldserver, with proper startup ordering (depends_on + healthcheck + service_completed_successfully);

.env.example for configuring DB credentials, game data path.

Game data (maps/vmaps/mmaps/dbc) is mounted read-only from the host rather than baked into the image, keeping the image size reasonable and avoiding redistribution of extracted client data.

Type of change

• C++ fix / feature
• DB fix (SQL only)
• Build / CMake
• Documentation

Related issue

Testing

• Compiles without warnings
• Server boots successfully
• Tested in-game

Checklist

• One fix per PR — not mixed with unrelated changes
• SQL files follow the YYYY_MM_DD_NN_database.sql naming scheme
• No debug code or leftover TODOs