build: Fix boost dependency

Currently local build fails with a message:
"""
src/meson.build:16:14: ERROR: Include dir subprojects/boost_1_78_0/
does not exist
"""
The error is happening because the correct path for the includes should
not be "subprojects/boost_1_79_0/" but "../subprojects/boost_1_79_0/".
But such relative links are deprecated, therefore rewrite boost
dependency with its own packagefile.
Also boost library is required for the project build, therefore drop
"required: false" statement for the dependency.
And since boost is required for the libeStoragedErase, add boost_dep to
its dependencies.

Tested:
"meson setup build && cd build && meson compile" now works without any
issues.

Change-Id: Id0afda7563c944f3afc88cd1f59099794611525e
Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
diff --git a/.gitignore b/.gitignore
index cd1bc79..03fff9b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 /subprojects/*
 !/subprojects/*.wrap
 !/subprojects/.clang-tidy-ignore
+!/subprojects/packagefiles
 
 # build directory
 build*/*