Add umbrella README

Add ptpl-xattn-pma-p07 (PTPL-XAttn-PMA-B-p07)

Add ptpl-xattn-pma-p06 (PTPL-XAttn-PMA-B-p06)

Add ptpl-xattn-pma-p05 (PTPL-XAttn-PMA-B (p=0.5))

Add ptpl-xattn-perceiver-p07 (PTPL-XAttn-Perceiver-B-p07)

Add ptpl-xattn-perceiver-p06 (PTPL-XAttn-Perceiver-B-p06)

Add ptpl-xattn-perceiver-p05 (PTPL-XAttn-Perceiver-B (p=0.5))

Add ptpl-adaln-p07 (PTPL-AdaLN-B-p07)

Add ptpl-adaln-p06 (PTPL-AdaLN-B-p06)

Add ptpl-adaln-p05 (PTPL-AdaLN-B (p=0.5))

Add xattn-pma-p06 (XAttn-PMA-p06)

Add xattn-pma-p05 (XAttn-PMA-p05)

Add xattn-perceiver-p06 (XAttn-Perceiver-p06)

Add xattn-perceiver-p05 (XAttn-Perceiver-p05)

Add xattn-pma-p01 (XAttn-PMA (p=0.1))

Add xattn-perceiver-p01 (XAttn-Perceiver (p=0.1))

Add xattn-gsa-p01 (XAttn-GSA (p=0.1))

Add xattn-direct-p01 (XAttn-Direct (p=0.1))

Add adaln-flow-p05 (PixCell-Flow-GE-B-p05)

Add adaln-flow-p03 (PixCell-Flow-GE-B-p03)

Add adaln-flow-p02 (PixCell-Flow-GE-B-p02)

Add adaln-flow-p01 (PixCell-Flow-GE-B (p=0.1))

Add adaln-ddpm-p06 (PixCell-GE-B-p06)

Add adaln-ddpm-p05 (PixCell-GE-B-p05)

Add adaln-ddpm-p03 (PixCell-GE-B-p03)

Add adaln-ddpm-p02 (PixCell-GE-B-p02)

Add adaln-ddpm-p01 (PixCell-GE-B (p=0.1))

Add pixcell-flow-b (PixCell-Flow-B)

Add pixcell-b (PixCell-B)

initial commit