In the admin section, when clicking on a link that leads to a page in
the public area, sometimes the page was opened in the same window and
sometimes it would open in a new window, with no clear criteria
regarding when either scenario would take place.
This was really confusing, so now we're more consistent and open
(almost) every link in the same window. The main reason behind it is
simple: if we add `target: _blank`, people who want to open those links
in the same window can no longer do so, so we're taking control away
from them. However, if we don't add this attribute, people can choose
whether to open the link on the same tab or to open it on a new one,
since all browsers implement a method to do so.
More reasons behind this decision can be found in "Opening Links in New
Browser Windows and Tabs" [1].
We're keeping some exceptions, though:
* Opening the link to edit an investment on the same tab would result in
losing all the investment filters already applied when searching for
investments, so until we implement a way to keep these filters, we're
also opening the link to edit an investment in a new tab
* For now, we're also opening links to download files in a new window;
we'll deal with this case in the future
[1] https://www.nngroup.com/articles/new-browser-windows-and-tabs/
