Translate all the user interface to Spanish

Some labels in the user interface were in Spanish and some in English.
This commit standardizes the language used to Spanish, translating every
label to that language.

pom.xml

@@ -4,7 +4,7 @@
 	<groupId>es.uvigo.esei.daa</groupId>
 	<artifactId>example</artifactId>
 	<packaging>war</packaging>
-	<version>0.1.4</version>
+	<version>0.1.5</version>
 	<name>DAA Example</name>
 
 	<licenses>

src/main/webapp/index.html

@@ -13,13 +13,13 @@
 		<form class="form-singin" action="main.html" method="POST">
 		  <h1 class="h1 mb-3 font-weight-normal">DAA Example</h1>
 		  
-			<label for="login" class="sr-only">Login</label>
-			<input id="login" name="login" type="text" class="form-control" placeholder="Login" required autofocus />
+			<label for="login" class="sr-only">Usuario</label>
+			<input id="login" name="login" type="text" class="form-control" placeholder="Usuario" required autofocus />
 			
-			<label for="password" class="sr-only">Password</label>
-			<input id="password" name="password" type="password" class="form-control" placeholder="Password" required />
+			<label for="password" class="sr-only">Contraseña</label>
+			<input id="password" name="password" type="password" class="form-control" placeholder="Contraseña" required />
 			
-			<button type="submit" class="btn btn-lg btn-primary btn-block mt-3">Login</button>
+			<button type="submit" class="btn btn-lg btn-primary btn-block mt-3">Entrar</button>
 		</form>
 	</body>
 </html>
\ No newline at end of file

src/main/webapp/main.html

@@ -15,14 +15,14 @@
 					   <strong>DAA Example</strong>
 					</a>
 					
-          <a id="#logout" href="logout" class="btn btn-dark" role="button">Logout</a>
+          <a id="#logout" href="logout" class="btn btn-dark" role="button">Cerrar sesión</a>
 				</div>
 			</div>
 		</header>
 
 		<div class="container">
 			<div id="people-container">
-				<h1 class="display-5 mt-3 mb-3">People</h1>
+				<h1 class="display-5 mt-3 mb-3">Personas</h1>
 			</div>
 		</div>