Fixes after a code review:
- Replaced strcmp with strncmp
- fixed the return type for "is_vzw_lte" function

Fixed the logic for parsing single-part and multi-part messages for LVW3 and LNA3.
Now single-part messages should be parsed as correctly as multi-part messages.

This logic improves the logic that were previously implemented in with multi-part messages
support for LVW2: bbf6ae9b1790c7129bf249641350b302def3ee27.

What changed:

- CDMA-specific SMS Teleservice ID is now saved as part of the PDU structure
- SMS Teleservice ID is now used to determine if the message
  CDMA Wireless Enhanced Messaging Teleservice (WEMT) with an actual UDH header
- UDH headers are used for multi-part messages in LVW3/LNA3

Why changed:

- UDH header may NOT be present in the SMS PDU
- first byte of user data may be a letter instead of the UDH header size
- when letter is parsed as side we get a lot of issues with
  segmentation faults, parsing issues, garbage in payload and so on
- so this commit adds SMS type detection before actual UDH header parsing attempt is performed

Sources for implementation:

- Telit LE910 V2 SERIES AT COMMANDS REFERENCE GUIDE 80446ST10707A Rev.3,
  section 5.1.5.5.7 Read Message (3GPP2) - +CMGR contains definition of Teleservice ID
  field and four of the types: 4097 page, 4098 SMS (0x1002), 4099 voice mail,
  262144 voice mail notification
- 3GPP2 X.S0004-550-E, section 2.256 SMS_TeleserviceIdentifier contains definition for
  additional SMS types including 4101 (0x1005) CDMA Wireless Enhanced Messaging Teleservice (WEMT).
- Teleservice ID 0x1002 is actually used for short messages in Verizon:
  ```+CMGL: 12,1,"",23

098010310REDACTED4F3 191213 050558 1002 0009 0C D4F29C0E32CBDF6D503508```

- Teleservice ID 0x1005 is actually used for multi-part messages in Verizon:
  ```+CMGL: 13,1,"",152
098010310REDACTED4F3 191213 050741 1005 0009 A0 05 00 03 4A 02 01 CC 66B3D96C369BCD66B3D96C369BCDE6E3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCFE7F3F97C3E9FCF

+CMGL: 14,1,"",143
098010310REDACTED4F3 191213 050743 1005 0009 95 05 00 03 4A 02 02 CE E7F3F97C3E9FCFE7F3F97C3E9FCFE7B3D96C369BCD66B3D96C369BCD66B3D96C369BCDE670381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E170381C0E87C3E17038168BC562B1582C168BC562B1582C1603```

Updated sms-utils to fix the issue with SMS messages on LVW3.

Switched from dynamically-allocated to statically-allocated variables for data fetched from the modem.

Added support of Quectel-specific commands into the "atcmd_plus_iccid_read()" function

- Added new "manufacturer" field to the "global_core" structure
- Added the "atcmd_plus_gmi_read()" function to fetch manufacturer identification
- Added a call to the "atcmd_plus_gmi_read()" in "sms_atcmd_init()"
- Added "is_telit_model()" and "is_quectel_model()" functions to pick
  a proper manufacturer-specific command in "atcmd_plus_iccid_read()" and,
  possibly, other commands in the future
- Tabs VS spaces. This project uses tabs

Discovered in portal case #5072165
https://support.multitech.com/support/case.html?action=view&id=72165