Add more esp32 examples

[bytedream]

This PR adds more examples for the esp32 platform.

It introduces an optional esp32 feature to the examples/apps crate that influences the hardcoded L2CAP MTU and is intended to be set by the esp32 examples only. The current MTU of 128 causes a BleHost(Hci(Unsupported Feature or Parameter Value)) error here when using an esp:

trouble/host/src/host.rs

Lines 813 to 820 in aaf2d02

	HostBufferSize::new(
	host.rx_pool.mtu() as u16,
	0,
	config::L2CAP_RX_PACKET_POOL_SIZE as u16,
	0,
	)
	.exec(&host.controller)
	.await?;

This is a known limitation, as seen in an issue comment over at the esp-idf repo espressif/esp-idf#942 (comment). They wrote that any total host buffer size <= 1021 bytes aren't safe to use (1017 bytes ACL MTU + 4 bytes ACL Data Packet header) as long as ACL packet segmentation isn't implemented, so I've set the MTU to 1017 if the esp feature is activated.
I tested my changes with an ESP32C3 and ESP32S3 and in both cases I was able to use a lower MTU than 1017 but it still failed at 128 (200 failed too, 512 not)

[lulf]

Thanks!

[lulf]

/test