dsputil: Move thirdpel-related bits into their own context
dsputil: Move hpel_template #include out of dsputil_template

Multiple inclusion makes no sense as it is only used in the 8-bit case.
dsputil_template: Remove bit depth ifdeffery and only consider 8-bit case

The template is only instantiated for the 8-bit case
Add missing headers to make template files compile (more) standalone
dsputil_template: Detemplatize the code

The indirection makes no sense withough multiple instantiation.
hpeldsp_template: Detemplatize the code

The indirection makes no sense withough multiple instantiation.
hpeldsp_template: Drop unused *_no_rnd_pixels16_8_c functions
hpeldsp_template: Move content to hpeldsp

There is no point in having this separate; it is not used as a template.
dsputil: Split off HuffYUV decoding bits into their own context
dsputil: Split off HuffYUV encoding bits into their own context
svq1enc: Rename SVQ1Context to SVQ1EncContext

This allows making it visible without name clashes.
dsputil: Move SVQ1 encoding specific bits into svq1enc
dsputil: Move ff_alternate_*_scan tables to mpegvideo
dsputil: Move mspel_pixels_tab to the only place it is used
dsputil: Move APE-specific bits into apedsp
vc1dsp: arm: Remove one pointless level of init indirection
dsputil: Move bink-specific add_pixels8 to binkdsp
WIP: split off dsputilenc
x86: mpegvideoenc: Change SIMD optimization name suffixes to lowercase
dsputilenc: Move *_8x8basis to the only place it is used