[electrophysiology_browser] Add help directory and missing docs (aces…

…#6773)

Add help content to electrophysiology_browser module.

    Resolves aces#6676

modules/electrophysiology_browser/help/electrophysiology_browser.md

@@ -0,0 +1,5 @@
+# Electrophysiology Browser
+
+This module allows you to review, filter and download EEG recordings and metadata.  Downloads are organized according to the EEG-BIDS standard. 
+
+Individual sessions can be accessed by clicking on the *raw* (for raw datasets) or *all types* (for all data) links of one of the rows under the links column, which will redirect you to the *View Session* page.

modules/electrophysiology_browser/help/sessions.md

@@ -0,0 +1,14 @@
+# View Session
+
+This page displays information from an individual recording session.
+
+Summary information about the candidate, the recording session and the hardware used is displayed.
+
+Files can be downloaded containing only the recording signal, the events, or other metadata, or all files compressed together, for the current session. These files are organized according to the EEG-BIDS standard (more information on the standard can be found [here](https://www.nature.com/articles/s41597-019-0104-8)), and are available for download as follows:
+
+- All files (tgz): a compressed folder containing all the recording data as well as the metadata for the EEG scan session.
+- EEG: the file containing the session recording data.    
+- Electrode info (tsv): contains electrode locations.    
+- Channels info (tsv): channel status and filter settings.    
+- Events (tsv): events (both stimuli and responses) recorded during the session.   
+