RND-168 Add dell icons css file

[leon-good-life]

Description

Jira ticket: https://cloudifysource.atlassian.net/browse/RND-168

Other PRs

cloudify-cosmo/cloudify-stage#2494

Screenshots / Videos

Checklist

• My code follows the UI Code Style.
• I followed the UI Testing Guidelines and verified that all tests/checks have passed.
• I verified if that change requires any update in the documentation.
• I added proper labels to this PR.

Tests

N/A

Documentation

Will be done at the same time of finalising the PR in cloudify-tage.

[Vorbert-Kruk]

As @leon-good-life you may have some agreements with @qooban, when it comes to the implementation of dell's icons, I'd like to wait till @qooban would review this PR
I may have some suggestions already, but I'd want to make sure that they wouldn't be commented unnecessarily

[qooban]

@leon-good-life I talked with Alex M. today and I'd like to say: please don't worry about RND-168, it's not critical item, it's not planned for 7.0. Put work aside and spend time with your girlfriend and enjoy your vacation! 🙂

[Vorbert-Kruk]

@leon-good-life I talked with Alex M. today and I'd like to say: please don't worry about RND-168, it's not critical item, it's not planned for 7.0. Put work aside and spend time with your girlfriend and enjoy your vacation! 🙂

Yeah, I'd say the same thing @leon-good-life
Enjoy your vacation and don't worry about the work stuff :)

[qooban]

I'm still not sure how we will do the switch to DDS, but... not to block you I'm approving this PR.

[qooban]

@leon-good-life Before merging and releasing new minor version, please make sure it works properly with Stage.