Adds "Locate File" input to every browse directory view in Diffusion

Summary:
Ref T15645

The very helpful "Locate File" input in Diffusion was so far only visible in the homepage route of any repository (/repository).

With this revision you can now locate a file from every browsed directory and in any selected commit.

The finder was already "directory sensitive" meaning: if you are trying to locate a file from within a browsed directory, only the children of this path will be searched.

For the searching in a specified commit (for example: https://we.phorge.it/source/phorge/browse/master/src/;05f4d5071fdca02123bd1ff4c0935b847c7f9963), I had to do a little JS magic adding the commit to the URI on the client side.

Test Plan: Checkout, browse through your repos with Diffusion trying to find files. (I tested only with Git repos.)

Reviewers: O1 Blessed Committers, speck

Reviewed By: O1 Blessed Committers, speck

Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15645

Differential Revision: https://we.phorge.it/D25521