feat: add provider system

lua/chai/providers.lua

@@ -0,0 +1,26 @@
+local M = {}
+
+local config = require('chai.config')
+
+local provider_instances = {}
+
+-- lazy loads providers of course
+function M.get_provider(name)
+    if provider_instances[name] ~= nil then
+        return provider_instances[name]
+    end
+
+    if config.options.providers[name] == nil then
+        error('unknown provider')
+    end
+
+    local provider_config = config.options.providers[name]
+
+    local provider = require('chai.providers.' .. provider_config.type)
+
+    local provider_instance = provider.init(provider_config)
+    provider_instances[name] = provider_instance
+    return provider_instance
+end
+
+return M