update sponsors list following OASIS audit

[jorydotcom]

This PR updates the list of OSLC sponsors which reflects current OP sponsorship & OASIS member participation per OASIS records.

• removes members who have dropped their membership
• adds members and sponsors who have joined to list
• adds logo image as permitted by sponsor

[jorydotcom]

Hi @berezovskyi can you confirm my last push addressed the changes you requested?

[berezovskyi]

my apologies @jorydotcom for the delay!