Improve web UI

[slatian]

Includes the following patches:

• .View variable in templates (to make some deduplication possible)
• Deduplicated the navigation and search-form
• The tagline is now a paragraph instead of an h2

NOT included are (these will be followup PRs):

• a 404 page, the patch inserts code in places that were changed by Feature: advanced search #13 and Feature: advanced search with rank selector #14, I'll submit it once one of those has either been merged or rejected. diff
• the patch introducing error messages for the case when no results are available, it also depends on one of either Feature: advanced search #13 or Feature: advanced search with rank selector #14 diff
  Let me know if you want only one, none or both of those.

[cblgh]

@slatian When adding interface changes, can you also include a screenshot in the PR? Simplifies reviewing a ton!

[slatian]

@cblgh This will not affect the visuals of Lieu (I should have mentioned that).

The changes here make it easier to modify (as in customizing/theming) and extend Lieu Templates (needed by my 404 page patch and the error messages patch), those will introduce some minor changes. (The "big" one of them being an additional margin on paragraphs to make the error messages readable)

[cblgh]

@slatian ah! i admit i punted on reviewing the code (having already gone through the other PRs i was feeling done for the moment hehe). thanks for the extra context! i'll review this next Lieu pass i do

[cblgh]

@slatian hiyo! prompted by #21 i'll be returning to reviewing this on Lieu. any idea where this PR was at? you mention some things not being included, is that still the case? or can this be merged as-is after the merge conflicts have been resolved

[slatian]

This one is a little template cleanup that sets the stage for the patches that I mentioned above were not included. The 404 page and error messages depended on the advanced search feature which wasn't merged at the time, that is why I explicitly mentioned that they weren't included, I'll submit both once I have a little more time on hand.

Lot of words nothing said: This one can be merged.

Edit: I was waiting with the other patches so that I can submit the others fir a fresh rebase (Also they both depend on the view variable as far as I remember). I'm doing it this way to avoid another mega PR with multiple features in one "blob"

[slatian]

I'm still interested in pushing the patches that depend on this once it gets merged. In case you want them as bigger PR package that is fine on my end, too. (the reason for splitting was that more than one feature depends on the functionality in here)