Add icon and add reference in readme and manifest

[bergmeister]

PR Summary

@adilio was kind enough to create a logo. This adds it to the main readme so that it is visible when browsing it to the repo and the module manifest so that it appears on the PSGallery.
The logo was taken from his repo, which is under MIT:
https://github.com/adilio/ps-design/tree/master/psscriptanalyzer
I have tested that the icon gets displayed correctly by uploading this test module: https://www.poshtestgallery.com/packages/foo/0.0.5

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Change is not breaking
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.

[adilio]

Hey @bergmeister, the icon in the test PSGallery is.... umm.... triggering my OCD 😅.

If you'd like to get the dimensions required, I can create a properly-scaled file for you?

Also, just thought I'd pass on that, when placing an img HTML tag referencing images, I find it's easier to just define one dimension. That way, the other dimension is automatically calculated to be the correct ratio, and you don't have to worry about pixelation from slight differences.

Just my 2 pesos 🙂.

[bergmeister]

Thanks for the tip with the img tag, that makes it easier.
I am not sure what the requirements are for the PSGallery but to me it seems that they resize the image to be square. Do you have a preference on being acknowledged in a certain way (e.g. to have a Readme in the assets folder to point to your original source)

[adilio]

Understood. I have just pushed two new versions to the repo. Both have a square base image size, so it won't skew images at all. One is original size, one is at 300px.

https://github.com/adilio/ps-design/blob/master/psscriptanalyzer/pssa-logo-square.png
https://github.com/adilio/ps-design/blob/master/psscriptanalyzer/pssa-logo-square-300.png

[bergmeister]

Thanks @adilio
I updated the logo in the published test module and in this PR to use the new square logo. This is how it'd look like now:
https://www.poshtestgallery.com/packages/foo/0.0.5