rp2xxx: PIO: Support more directives

[Grazfather]

From 11.3.1 in the RP2350 [datasheet](https://pip-assets.raspberrypi.com/categories/1214-rp2350/documents/RP-008373-DS-2-rp2350-datasheet.pdf?disposition=inline]:

.define (PUBLIC) <symbol> <value>
.clock_div <divider>
.fifo <fifo_config>
.mov_status rxfifo < <n>
.mov_status txfifo < <n>
.mov_status irq <(prev|next)> set <n>
.in <count> (left|right) (auto) (<threshold>)
.program <name>
.origin <offset>
.out <count> (left|right) (auto) (<threshold>)
.pio_version <version>
.set <count>
.side_set <count> (opt) (pindirs)
.wrap_target
.wrap
.lang_opt <lang> <name> <option>
.word <value>

Many of these are new to rp2350.

Also, some seem redundant: e.g. What is the purpose of .set <count> if we are setting it explicitly in SET_COUNT?

I noticed this when I found the bug fixed in #736: whether side set is optional is ONLY set in the directive, but the count is set twice, once in the program, once when setting up pins with PinMappingOptions. I don't know if we do anything with the value collected from the directive.