Improvements for InputStreamAdaptive

[CastagnaIT]

1. inputstream.adaptive.manifest_type is deprecated on Kodi 21 and removed on Kodi 22
2. Add missing mimetype for smoothstreaming
3. Handle user-agent header also on inputstream.adaptive.manifest_headers, this is often a requirement for services, set it only to inputstream.adaptive.stream_headers has no much sense because most of the time will not works
4. Always set useragent headers and mimetype for inputstream.adaptive, see code comment.

Some code could be simplified a bit if Use inputstream.adaptive for m3u8 (HLS) streams setting would instead support all ISA manifest formats, so convert that setting as: Use inputstream.adaptive for streams. I havent done this change since i have not full picture of the reasons behind this choice (limited to HLS), also i want allow PR to be backported without breaking changes.

this pr could be also backported to Omega as is without problems

fix #871

[phunkyfish]

Looks good. Backporting is entirely up to you.

if you’d like this released please add a changelog entry and the verison bump.

[CastagnaIT]

Looks good. Backporting is entirely up to you.

if you’d like this released please add a changelog entry and the verison bump.

i will do, but i wait some days to see if the user of issue give a feedback

[CastagnaIT]

@phunkyfish if you want re-review, i add another commit to fix isa headers/mimetype for all use cases

[phunkyfish]

LGTM

[CastagnaIT]

verson bump commit added here and also on backport PR