[neomutt] added basic config

Shamelessly copied from https://gideonwolfe.com/posts/workflow/neomutt/intro/

.config/neomutt/mappings.example

@@ -0,0 +1,58 @@
+# vi: filetype=muttrc
+
+# General rebindings
+bind attach <return> view-mailcap
+bind attach l view-mailcap
+bind editor <space> noop
+bind pager c imap-fetch-mail
+bind index G last-entry
+bind index g noop
+bind index gg first-entry
+bind pager,attach h exit
+bind pager j next-line
+bind pager k previous-line
+bind pager l view-attachments
+bind index D delete-message
+bind index U undelete-message
+bind index L limit
+bind index h noop
+bind index l display-message
+bind browser h goto-parent
+bind browser l select-entry
+bind pager,browser gg top-page
+bind pager,browser G bottom-page
+bind index,pager,browser d half-down
+bind index,pager,browser u half-up
+bind index,pager R group-reply
+bind index \031 previous-undeleted	# Mouse wheel
+bind index \005 next-undeleted		# Mouse wheel
+bind pager \031 previous-line		# Mouse wheel
+bind pager \005 next-line		# Mouse wheel
+bind editor <Tab> complete-query
+
+
+# sidebar mappings
+bind index,pager \Ck sidebar-prev
+bind index,pager \Cj sidebar-next
+bind index,pager \Co sidebar-open
+bind index,pager \Cp sidebar-prev-new
+bind index,pager \Cn sidebar-next-new
+bind index,pager B sidebar-toggle-visible
+
+# global index and pager shortcuts
+bind index,pager @ compose-to-sender
+bind index,pager D purge-message
+bind index <tab> sync-mailbox
+bind index <space> collapse-thread
+
+# Email completion bindings
+bind editor <Tab> complete-query
+bind editor ^T complete
+
+# Press A to add contact to Khard address book
+macro index,pager A \
+    "<pipe-message>khard add-email<return>" \
+    "add the sender email address to khard"
+
+## Shortcuts
+macro index,pager <f2> '<sync-mailbox><enter-command>source ~/.config/neomutt/accounts/example<enter><change-folder>!<enter>'