refactor!: remove default gitlab host, add error

src/core/http-client/httpClient.axios.ts

 import axios, { AxiosInstance } from 'axios'
+import { Problem } from '../exceptions'
 import { HTTPClient, HTTPClientConfig, HTTPResponse, RequestConfig } from './httpClient.interface'
 
 export class AxiosHTTPClient implements HTTPClient {
@@ -6,19 +7,27 @@ export class AxiosHTTPClient implements HTTPClient {
 
   constructor(readonly config: Partial<HTTPClientConfig> = {}) {
     this.instance = axios.create({
-      baseURL: (config.host || 'https://gitlab.univ-nantes.fr') + '/api/v4',
+      baseURL: config.host + '/api/v4',
       headers: {
         Authorization: `Bearer ${config.accessToken}`,
       },
     })
   }
 
+  private checkConfiguration() {
+    if (!this.config.host) {
+      throw new Problem('No configuration found. Please configure the Gitlab host to use.')
+    }
+  }
+
   async get<T>(path: string, config?: RequestConfig): Promise<HTTPResponse<T>> {
+    this.checkConfiguration()
     const { data, headers, status } = await this.instance.get(path, config || {})
     return { data, headers, status }
   }
 
   async post<T>(path: string, config?: RequestConfig): Promise<HTTPResponse<T>> {
+    this.checkConfiguration()
     const { data, headers, status } = await this.instance.post(path, config?.body, config || {})
     return { data, headers, status }
   }