Header implementation - desktop (#47)

* beginning header

* began with header

* header design completed, waiting for pull from main

* header completed

* changed and removed some jquery

* removed images

* corrected linting errors

* added announcement + header logo is a link to homepage

* separated header css file

* rems of announcement adjusted

* font size of announcement adjusted

* changes made based on comments

* changes css specificity

* added icons to files

* js added to underline nav link when path matches

* changed to class in mobile css

* changes made based on comments

* Update announcement.css removed commented out css

* Update announcement.css to dark variable

Author: MariamM110

.eslintignore

@@ -0,0 +1,2 @@
+assets/js/search.js
+assets/js/bioconductor.js

.stylelintignore

@@ -1 +1,2 @@
-assets/style/bioconductor.css
+assets/style/bioconductor.css
+