.NET: Remove bad image links from docs
# Apache Ignite.NET
-<img src="https://ignite.apache.org/images/logo3.png" hspace="20" /><img src="https://ptupitsyn.github.io/images/net-framework.png" hspace="20" />
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Apache Ignite is a [memory-centric](https://ignite.apache.org/arch/memorycentric.html) distributed database,
[caching](https://ignite.apache.org/features/datagrid.html), and processing platform for transactional, analytical,
and streaming workloads, delivering in-memory speeds at petabyte scale.
