Revert "Simplify and unify markup on the pages by propagating "content" identifier."

This reverts commit f0d2265.

We can't use #content together with .col-sm-12 because they produce horizontal scroll. I don't know
how to fix it, so decided to just revert the changes.

Fix #797

[ci skip]

Author: php-coder

src/main/webapp/WEB-INF/views/collection/info.html

@@ -60,9 +60,9 @@
 				</div>
 			</div>
 			<div class="row">
-				<div id="content" class="col-sm-12">
+				<div class="col-sm-12">
 
-					<h3 th:text="#{t_collection_of(${ownerName})}">
+					<h3 class="text-center" th:text="#{t_collection_of(${ownerName})}">
 						John Doe's collection
 					</h3>
 

src/main/webapp/WEB-INF/views/series/search_result.html

@@ -64,8 +64,8 @@
 				</div>
 			</div>
 			<div class="row">
-				<div id="content" class="col-sm-12" th:with="search_results=#{t_search_results}">
-					<h3 th:text="${#strings.capitalize(search_results)}">
+				<div class="col-sm-12" th:with="search_results=#{t_search_results}">
+					<h3 class="text-center" th:text="${#strings.capitalize(search_results)}">
 						Search results
 					</h3>