(fix) implement various fixes as per qa review

closes #1827 (closed)

👇🏼 Issues that shoul be fixed:

• The header is the wrong colour. Should be the same as the background itself. Compare two screenshots below.

• Password screen should group 'Current Password' and 'New password' separately. Currently there are morphed into one. Also, there seems to be the issue of 'double borders' between the input fields. Compare screenshots below.

• The spacing left and right of each notification item looks quite tight in the implementation. It should be increased to match the designs. See below screenshots.

Other:

👇🏼 These options are not part of the navigator that we are using.

• For any sub-screen, e.g. Account, the heading should be positioned in the centre of the screen, and not towards the left.

• Heading should be in centre for the individual settings screens.

• Confirm that the weight of the page headings, matches the designs. I can't quite confirm, but the implementation looks a little lighter that the design itself. See above screenshots

👇🏼 We don't use native picker because they are different for each platform and android doesn't look well

• When selecting a language, is it not possible to use the native picker? See designs.