apphandler: use regex to parse firmware version

1. Use regular expression to parse firmware major & minor version.
2. Add meson option to modify regex string by platform layer.

Tested result:

- parsing result of version 1: v0.6-19-gf363f61-dirty
rev.major = 0
rev.minor = 6

- parsing result of version 2: v1.99.10-113-g65edf7d-r3-0-g9e4f715
rev.major = 1
rev.minor = 99

- parsing result of version 3: 2.14.0-dev
rev.major = 2
rev.minor = 14

Change-Id: I1a5ebd592e3078d38182926a6a9ee98a129c3ee4
Signed-off-by: Potin Lai <potin.lai@quantatw.com>
diff --git a/meson.build b/meson.build
index 4889b97..55d25b0 100644
--- a/meson.build
+++ b/meson.build
@@ -32,6 +32,7 @@
 conf_data.set_quoted('HOST_NAME', get_option('host-name'))
 conf_data.set_quoted('POWER_READING_SENSOR', get_option('power-reading-sensor'))
 conf_data.set_quoted('HOST_IPMI_LIB_PATH', get_option('host-ipmi-lib-path'))
+conf_data.set_quoted('FW_VER_REGEX', get_option('fw-ver-regex'))
 
 conf_h = configure_file(
   output: 'config.h',