Fix two TI DSBGA footprints and add a third one.

This MR affects three FPs. There are two bugfixes and one new addition.

This fixes #2583 (closed) and supersedes !2910 (closed)

Texas_DSBGA-10_1.36x1.86mm_Layout3x4_P0.5mm and Texas_DSBGA-12_1.36x1.86mm_Layout3x4_P0.5mm had some issues:

1. Their orientation mark is not on pad A1 but on pad A3, but the FPs had the orientation feature on pad A1.
2. The silkscreen was too close to the pads
3. They didn't specify the TI package code in their description, making them easy to confuse with other fps
4. The mask specification was not entirely correct (datasheet specified a maximum, but this was used as the nominal value)

The two footprints were regenerated using a script (see kicad-footprint-generator!798) and then manually edited to move the orientation feature and add a silkscreen marker on pad A1 (consistent with other FPs where the orientation mark is not at pad 1/A1). At the same time, another fp was generated - Texas_DSBGA-16_2.39x2.39mm_Layout4x4_P0.5mm - this is the FP that a contributor added in !2910 (closed) (thanks @Bnjamn!) but a few issues with it were fixed.

Relevant documents:

• http://www.ti.com/lit/ds/symlink/ts3a24159.pdf
• http://www.ti.com/lit/ds/symlink/txb0104.pdf
• https://www.ti.com/lit/ds/symlink/dac80508.pdf
• http://www.ti.com/lit/an/snva009ag/snva009ag.pdf

Screenshots:

Old parts

New parts

Script-reported KLC violations:

F5.2: Part is too small for larger reference on FAB layer

F6.3: Pads have separate paste aperture because paste shape is different from pad shape