emacs:theme: Add dark custom theme - mytheme-dark

- Add my own custom dark theme. This is based on wombat theme.
- Add other custom variables as well.
- Make all the themes as safe by default.
emacs:package: improved init package list install

Improve initial essential package installation. This will
refresh the package archive list before installation.

Signed-off-by: Ratheesh S <ratheeshreddy@gmail.com>
emacs: correct user email and user name

Signed-off-by: Ratheesh S <ratheeshreddy@gmail.com>