Refactor vocations: Reload, extracted into tfs::game::vocations namespace and code improvements

[ramon-bernardo]

Pull Request Prelude

• I have followed proper The Forgotten Server code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

• Namespace: Introduced tfs::game::vocations namespace to organize vocation-related logic in a more structured way.
• Smart pointers: Transitioned from raw pointers to std::shared_ptr for improved memory management and safety.
• Loading vocations: Implemented load_from_xml(...) to load vocation data from an XML file, with an option to reload existing data.
• Searching vocations:
  • Renamed functions for finding vocations by ID and name:
    • find_by_id(uint16_t id)
    • find_by_name(std::string_view name)
    • find_by_promoted_id(uint16_t id)

Note: It is not possible to delete a vocation at runtime; only to modify or add new ones.

Before reload.

After changed and reload.

Usage

// Load vocation data from XML (reload set to false).
std::ifstream is{"data/XML/vocations.xml"};
tfs::game::vocations::load_from_xml(is, "data/XML/vocations.xml");

// Find a vocation by ID and check if it's valid.
auto vocation = tfs::game::vocations::find_by_id(1);
if (vocation) {
    std::cout << "Found vocation: " << vocation->name << std::endl;
}

// Find a vocation by name.
auto knight = tfs::game::vocations::find_by_name("Knight");
if (knight) {
    std::cout << "Found vocation: " << knight->name << std::endl;
}

// Check skill tries and mana requirements for a specific vocation.
auto skill_tries = vocation->getReqSkillTries(SKILL_SWORD, 20);
auto mana_req = vocation->getReqMana(5);

// Remove vocations or reload them from XML.
std::ifstream is{"data/XML/vocations.xml"};
tfs::game::vocations::load_from_xml(is, "data/XML/vocations.xml", true);

[ramon-bernardo]

The future idea is to move most or all of Vocation to lua, removing it from the core