[pvr] PVR Addon API 5.7.1: Support for passing MimeType for PVR streams

[peak3d]

Description

Allow setting Mime-Type for PVR streams + Disable Content-Lokup for known streams.

Todos for addon maintainers: none, as minimum pvr api version number did not change.

Motivation and Context

Mime-Type content lookup takes some time (HEAD Request) and can be supressed if PVR addon knows the mime type. Speeds up channel switching.

Should not lead to version issues because PVR_VERSION_MIN is unchanged.

How Has This Been Tested?

pvr.zattoo + mpeg DASH streams

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

[ksooo]

Next time, please don't forget to label the PR "PVR Addon API change". And I always explain in detail in the description of such PRs what the changes mean exactly for the PVR Addon maintainers (assuming they read PRs flagged "PVR API change") - for instance, whether addon code must be adjusted and how or whether a recompile of the addon is sufficient.