Refactor Project API to reflect changes upstream

projectile-project-root no longer returns `default-directory` if not in
a project (it returns nil). As such, doom-project-* functions (and their
uses) have been refactored.

+ doom-project-p & doom-project-root are aliases for
  projectile-project-p & projectile-project-root.
+ doom-project-{p,root,name,expand} now has a DIR argument (for
  consistency, since projectile-project-name and
  projectile-project-expand do not).
+ The nocache parameter is no longer necessary, as projectile's caching
  behavior is now more sane.
+ Removed some projectile advice/hacks that are no longer necessary.
+ Updated unit tests

modules/lang/org/autoload/org-capture.el

@@ -82,7 +82,7 @@ you're done. This can be called from an external shell script."
      filename
      (or (locate-dominating-file (file-truename default-directory)
                                  filename)
-         (if (doom-project-p 'nocache) (doom-project-root 'nocache))
+         (doom-project-root)
          (user-error "Couldn't detect a project")))))
 
 ;;;###autoload