Move to Bootstrap 4

Bootstrap < 4.1.2 has the following CVE:
https://nvd.nist.gov/vuln/detail/CVE-2018-14041

Removed bootstrap-theme.css due to "Replaced the separate optional
theme with configurable options via SCSS variables
(e.g., $enable-gradients: true)."

Added "width: 100%" to a few places where width 100% was no longer
getting inherited.
Moved a few elements and adjusted styles to get the same look as
before.

See https://getbootstrap.com/docs/4.0/migration/ for more
information.

Tested: Manually on a Witherspoon.
Change-Id: I0a72665ac1ca6eacd0b553a585b1fb15e14ae62c
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/app/common/directives/log-search-control.html b/app/common/directives/log-search-control.html
index 113e9f0..1184bda 100644
--- a/app/common/directives/log-search-control.html
+++ b/app/common/directives/log-search-control.html
@@ -1,9 +1,11 @@
-<p class="content-label">Filter events</p>
-<div class="content__search">
-  <label for="content__search-input">Event Log Search</label>
-  <input id="content__search-input" type="text" ng-model="customSearch" ng-keydown="doSearchOnEnter($event)"/>
-  <div class="search-submit__wrapper">
-    <button class="clear-input" ng-click="clear()">&#10005;</button>
-    <input id="content__search-submit" type="submit" class="btn btn-primary content__search-submit" value="Filter" ng-click="doSearchOnClick()"/>
+<section id="event-search" class="row column" aria-label="event log search">
+  <p class="content-label">Filter events</p>
+  <div class="content__search">
+    <label for="content__search-input">Event Log Search</label>
+    <input id="content__search-input" type="text" ng-model="customSearch" ng-keydown="doSearchOnEnter($event)"/>
+    <div class="search-submit__wrapper">
+      <button class="clear-input" ng-click="clear()">&#10005;</button>
+      <input id="content__search-submit" type="submit" class="btn btn-primary content__search-submit" value="Filter" ng-click="doSearchOnClick()"/>
+    </div>
   </div>
-</div>
+</section>