[FIX] RT-1206: Detect browser language preferences

1. Detect user's browser language settings, and if we have a translation available in that language, display client in that language
2. If we don't have a translation available, display client in English
3. If a invalid language was selected (such as navigate to `#/lang/abcdefg`), display client in default language (as 1 & 2).

* For languages with variants such as `zh-CN` and `en-US`, we will treat thoses as `zh` and `en`.
* A language alias map is introduced as the browser uses `zh` for Chinese but we use `cn` for Chinese.
[FIX] Navbar: Removed cashin reference
[FIX] RT-1730 Pull-Request

Take out unnecessary changes to validators directive
[CHORE] Fund/Accounts UI: Add template for new accounts tab
[FEATURE] Fund UI: Trust lines show up based on currency
[TASK] Fund UI: Add add trust UI
[TASK] Structural changes on fund/trust
Bookmark on account fund UI
[FIX] Fund: Navbar position fix
[TASK] Fund: Trust simple edit
[TASK] Fund: Add validation for simple edit
[TASK] Style: Update style on edit mode
[TASK] Fund: Optimize code
[FIX] Fund: Initial load of trustlines
[TASK] Fund UI: Add Delete button to account lines
[TASK] Fund: Simplify UI
[TASK] Accounts UI: Delete trustlines works
[TASK] Accounts UI: Update notifications
[TASK] Fund UI: Fix color on pending notification
[TASK] Fund: UI changes