Create/Configure language service for C# service implementation

[TheTechArch]

Functional architect/designer: @-mention
Technical architect: @TheTechArch @nkylstad

Description
We need to create (or configure) a language server for C# that can be used by the Monaco Editor in Altinn Studio. Monaco will use Monaco Language Client to call this server. This is done in #317

• We currently does not belive there exist any installed server online we can reuse.
• We currently does not belive there exist any existing server we can install as part of Altinn Studio without modification.

There exist open source project for the Language Service Protocool and for a Roslyn language server.

The most relevant project is Omnisharp Roslyn. According to this thread and this pull request it should now support LSP. (at least limited)

I have asked questions to see if the team can give feedback if this product is feasable or not.

Technical considerations
The server need to have access to local repo in the cloud.

Acceptance criterea

• The language server needs to support code completion
• It needs to follow the LSP standard for the implemented functionality
• It needs to have access to the files in the local repostory (Azure storage)
• It needs to support request comming for different C# projects at the same time.

Tasks

• Analyze if we can use omnisharp-roslyn directly
• If not, Analyze if it is possible to modify this project to support our requirements

[lvbachmann]

Note to self: Re-evaluate this once we know how likely it is that pilot service developers will write C# code in Monaco

[GGunnar]

@helenekri @sarahwoodhouse please check with the pilots regarding writing C# in Altinn Studio.

[TheTechArch]

Closing this. I dont belive this is relevant anymore.