Feature: Support partition images from self compiled Android ROM

[ttimasdf]

I've been trying to compile Android 9.0 for Nintendo Switch for the last week, but found it hard to flash the output images. One way is to flash the zip inside TWRP from a Switch installed Switchroot's release before, another is to flash separate img files when formatting sdcard with the script from this project. I'll try to modify the script first and record my progress here.

Partition images I found after building the ROM:

# ls -lh out/target/product/icosa/obj/PACKAGING/target_files_intermediates/lineage_icosa-target_files-eng.root/IMAGES/
total 1.4G
-rw-r--r--. 1 root wheel  11M Mar 24 15:20 boot.img
-rw-r--r--. 1 root wheel 129K Mar 24 15:21 cache.img
-rw-r--r--. 1 root wheel  18M Mar 24 15:20 recovery.img
-rw-r--r--. 1 root wheel  18M Mar 24 15:20 recovery-two-step.img
-rw-r--r--. 1 root wheel 1.2G Mar 24 15:21 system.img
-rw-r--r--. 1 root wheel 140K Mar 24 15:20 system.map
-rw-r--r--. 1 root wheel 2.5M Mar 24 15:21 userdata.img
-rw-r--r--. 1 root wheel 175M Mar 24 15:21 vendor.img
-rw-r--r--. 1 root wheel  42K Mar 24 15:21 vendor.map