Added keyboard field navigation for username, password textfield in bookmark view

[hosy]

Description

Added a inputAccessoryView for username and password text field for field navigation between these rows, also setting a ReturnTypeKey.

Related Issue

#48

Motivation and Context

Better navigation between text fields form keyboard, because next web view for oAuth 2 does also have this field navigators.

How Has This Been Tested?

• add or edit a bookmark
• set focus on username or password text field

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@f9ccc75). Click here to learn what that means.
The diff coverage is 62.85%.

@@            Coverage Diff            @@
##             master     #312   +/-   ##
=========================================
  Coverage          ?   29.57%           
=========================================
  Files             ?      229           
  Lines             ?    15521           
  Branches          ?        0           
=========================================
  Hits              ?     4590           
  Misses            ?    10931           
  Partials          ?        0

Impacted Files	Coverage Δ
ownCloud/Bookmarks/BookmarkViewController.swift	81.92% <62.85%> (ø)

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[codecov]

Codecov Report

Merging #312 into master will increase coverage by 0.09%.
The diff coverage is 70.27%.

@@            Coverage Diff             @@
##           master     #312      +/-   ##
==========================================
+ Coverage   29.86%   29.95%   +0.09%     
==========================================
  Files         228      228              
  Lines       15284    15321      +37     
==========================================
+ Hits         4564     4590      +26     
- Misses      10720    10731      +11

Impacted Files	Coverage Δ
ownCloud/Bookmarks/BookmarkViewController.swift	82.8% <70.27%> (-0.82%)	⬇️

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[jesmrec]

For me it is OK, but a tiny detail:

In the "Add account" scenario, you are lighting/shadowing the arrows like:

In case of "Edit account" with a basic auth server, there is no choice to move up/down through text fields, because only Password is enabled:

so, the blue up arrow does not do nothing. It should be shadowed/hidden...

Apart of that, this is OK for me.

[hosy]

@jesmrec I just fixed it. Accessory View is now only available, if the needed text fields are enabled.

[jesmrec]

Approved