Added 2 ffat partition schemes for 4MB modules + improved descriptions. (#2623)

* Added 2 ffat partition schemes for 4MB modules + improved descriptions.

Existing format options were unclear on how much spiffs you were
getting. Also add missing 1MB App/3MB Spiffs split.
This addresses https://github.com/espressif/arduino-esp32/issues/1799

This makes it very clear what each option gives you, and also adds 2 options
to get ffat on 4MB chips..

* Added link to ffat howto.

boards.txt

@@ -68,18 +68,27 @@ esp32.menu.PartitionScheme.default=Default with spiffs (4MB FLASH)
 esp32.menu.PartitionScheme.default.build.partitions=default
 esp32.menu.PartitionScheme.defaultffat=Default with ffat (4MB FLASH)
 esp32.menu.PartitionScheme.defaultffat.build.partitions=default_ffat
-esp32.menu.PartitionScheme.minimal=Minimal (2MB FLASH)
+esp32.menu.PartitionScheme.minimal=Minimal (1.3MB APP/700KB SPIFFS)
 esp32.menu.PartitionScheme.minimal.build.partitions=minimal
-esp32.menu.PartitionScheme.no_ota=No OTA (Large APP)
+esp32.menu.PartitionScheme.no_ota=No OTA (2MB APP/2MB SPIFFS)
 esp32.menu.PartitionScheme.no_ota.build.partitions=no_ota
 esp32.menu.PartitionScheme.no_ota.upload.maximum_size=2097152
-esp32.menu.PartitionScheme.huge_app=Huge APP (3MB No OTA)
+esp32.menu.PartitionScheme.noota_3g=No OTA (1MB APP/3MB SPIFFS)
+esp32.menu.PartitionScheme.noota_3g.build.partitions=noota_3g
+esp32.menu.PartitionScheme.noota_3g.upload.maximum_size=1048576
+esp32.menu.PartitionScheme.noota_ffat=No OTA (2MB APP/2MB FATFS)
+esp32.menu.PartitionScheme.noota_ffat.build.partitions=noota_ffat
+esp32.menu.PartitionScheme.noota_ffat.upload.maximum_size=2097152
+esp32.menu.PartitionScheme.noota_3gffat=No OTA (1MB APP/3MB FATFS)
+esp32.menu.PartitionScheme.noota_3gffat.build.partitions=noota_3gffat
+esp32.menu.PartitionScheme.noota_3gffat.upload.maximum_size=1048576
+esp32.menu.PartitionScheme.huge_app=Huge APP (3MB No OTA/1MB SPIFFS)
 esp32.menu.PartitionScheme.huge_app.build.partitions=huge_app
 esp32.menu.PartitionScheme.huge_app.upload.maximum_size=3145728
-esp32.menu.PartitionScheme.min_spiffs=Minimal SPIFFS (Large APPS with OTA)
+esp32.menu.PartitionScheme.min_spiffs=Minimal SPIFFS (1.9MB APP with OTA/190KB SPIFFS)
 esp32.menu.PartitionScheme.min_spiffs.build.partitions=min_spiffs
 esp32.menu.PartitionScheme.min_spiffs.upload.maximum_size=1966080
-esp32.menu.PartitionScheme.fatflash=16M Fat
+esp32.menu.PartitionScheme.fatflash=16M Flash (2MB APP/12.5MB FAT)
 esp32.menu.PartitionScheme.fatflash.build.partitions=ffat
 
 esp32.menu.CPUFreq.240=240MHz (WiFi/BT)

tools/partitions/ffat.csv

@@ -5,3 +5,4 @@ app0,     app,  ota_0,   0x10000, 0x200000,
 app1,     app,  ota_1,   0x210000,0x200000,
 eeprom,   data, 0x99,    0x410000,0x1000,
 ffat,     data, fat,     0x411000,0xBEE000,
+# to create/use ffat, see https://github.com/marcmerlin/esp32_fatfsimage

tools/partitions/noota_3g.csv

+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x5000,
+otadata,  data, ota,     0xe000,  0x2000,
+app0,     app,  ota_0,   0x10000, 0x100000,
+eeprom,   data, 0x99,    0x110000,0x1000,
+spiffs,   data, spiffs,  0x111000,0x2EF000,

tools/partitions/noota_3gffat.csv

+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x5000,
+otadata,  data, ota,     0xe000,  0x2000,
+app0,     app,  ota_0,   0x10000, 0x100000,
+eeprom,   data, 0x99,    0x110000,0x1000,
+ffat,     data, fat,     0x111000,0x2EF000,
+# to create/use ffat, see https://github.com/marcmerlin/esp32_fatfsimage

tools/partitions/noota_ffat.csv

+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x5000,
+otadata,  data, ota,     0xe000,  0x2000,
+app0,     app,  ota_0,   0x10000, 0x200000,
+eeprom,   data, 0x99,    0x210000,0x1000,
+ffat,     data, fat,     0x211000,0x1EF000,
+# to create/use ffat, see https://github.com/marcmerlin/esp32_fatfsimage